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Impact Of A Qtl For Plasticity Of Productive Tiller Number On Yield And Yield Competitive Ability Of Spring Wheat
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Book Synopsis Impact of a QTL for Plasticity of Productive Tiller Number on Yield and Yield Competitive Ability of Spring Wheat by : Afaf Mahdee Nasseer
Download or read book Impact of a QTL for Plasticity of Productive Tiller Number on Yield and Yield Competitive Ability of Spring Wheat written by Afaf Mahdee Nasseer and published by . This book was released on 2015 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heat and drought stress are important limitations on wheat growth and reproduction. Therefore, there is a need to understand mechanisms that enable wheat plant adapted to heat and drought stress, and maintain plant growth, development, and productivity during stress periods. One of the most important plasticity traits in wheat is productive tiller number (PTN). This thesis reports two studies. The goal of the first study was to test the impact of a previously identified allele for high productive tiller number on yield and yield components, agronomics, and seed quality traits, in a set of near isogenic lines developed in three genetic backgrounds, including the crosses Vida/McNeal, Reeder/Choteau, and Reeder/Hank. Results from nine field locations showed that high productive tiller allele on QTn.mst-6B enhanced early tiller (ETN) formation regardless of the locations. Under favorable conditions, the large number of early tillers transferred into a capacity for high productive tiller number, which may enhance grain yield. Seed number per head and seed weight was affected negatively by the high tiller allele at QTn.mst-6B over all locations, and thus more tillers did not always equate to higher yield. Moreover the high productive tiller allele on QTn.mst-6B associated with high dry weight of roots based on a greenhouse study. The goal for second study was to assess the impact of QTn.mst-6B under different competition levels and levels of available water. Five near-isogenic line (NIL) pairs for two genetic backgrounds (Reader/Choteau, Vida/McNeal) were selected randomly from the three populations of our first study. Three competition levels were imposed on the NIL pairs in replicated experiments. Competition levels were 1) bordered rows representing high competition and limited water, 2) non-bordered rows representing less competition and more available water, and 3) space-planted rows representing no competition and abundant water. The experiment was planted over three locations on 2012 and 2013. The ETN more often developed into PTN in conditions with less competition levels, while did not develop into PTN in conditions of high competition and low water. The high plasticity of PTN was associated with high plasticity in grain yield, and low plasticity of seed weight.
Book Synopsis Genetic Analysis of Productive Tiller Number and Green Leaf Duration Under Late-seasoned Heat and Drought Stress Environment in Spring Wheat by : Yukiko Naruoka
Download or read book Genetic Analysis of Productive Tiller Number and Green Leaf Duration Under Late-seasoned Heat and Drought Stress Environment in Spring Wheat written by Yukiko Naruoka and published by . This book was released on 2010 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate change is affecting the growing environment for spring wheat (Triticum aestivum L. em. Thell) in the northern Great Plains, challenging breeders to identify traits and genes that will allow reliable grain yield under drought and heat stress conditions. The first objective of this study was to evaluate the genetic basis of productive tiller number (PTN) and its relationship to economic traits under a wide range of environments. Correlation of PTN with economic traits was determined using three recombinant inbred line populations. Quantitative trait loci (QTL) analysis was conducted with a mapping population generated from a cross between Reeder and Conan. Our results showed a consistent positive correlation between PTN and grain yield under drought and heat stress conditions as well as well-watered conditions across three spring wheat populations. The major stable QTL, QTn.mst-6B, was consistent across environments and populations, and the positive allele from Reeder increased grain yield. The second objective of this study was to evaluate the genetic basis of green leaf duration (GLDAH) which has been reported as a drought and heat stress resistant trait in several crops. Additionally, the relationship of GLDAH to agronomic traits and a root trait was assessed using the Reeder/Conan population. Correlation analysis showed a positive relationship between GLDAH and test weight, seed weight, seed diameter under heat and drought stress conditions but not cool, well-watered conditions. In contrast, GLDAH had a neutral relationship with grain yield under the stress conditions, but showed negative correlation under well-watered conditions. Major QTL QGfd.mst-4A had a consistent effect under hot, dry conditions for the populations. The Reeder allele of QGfd.mst-4A resulted in longer GLDAH and also increased the amount of xylem exudate, indicating higher root mass and/or activity. These results suggested that i) QTn.mst-6B may be useful for improvement of spring wheat production under a wide range of environment and ii) QGfd.mst-4A may contribute to heat and drought stress resistance potentially through root function, but may negatively affect grain yield under well-watered conditions in the northern Great Plains of North America and similar environments.
Book Synopsis QTL Analysis of Wheat Grain Yield Components and Agronomic Traits Using Advanced Genotyping Platforms by : Kyle D. Isham
Download or read book QTL Analysis of Wheat Grain Yield Components and Agronomic Traits Using Advanced Genotyping Platforms written by Kyle D. Isham and published by . This book was released on 2019 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: The genetic manipulation of major yield components and agronomic traits is an important approach to increase wheat grain yield. Phenotyping of these traits is cost-effective but is time-consuming and the output is also confounded by environmental conditions. In the present study, we aimed to identify quantitative trait loci (QTL) and tightly linked, friendly used molecular markers to select for productive tiller number (PTN), fertile spikelet number per spike (fSNS), thousand kernel weight (TKW), grain yield (GY), height (HT), and heading date (HD). These traits were assessed in eight field trials over three years in a double haploid (DH) population that were derived from two adapted high yielding spring wheat cultivars 'UI Platinum' and 'LCS Star'. The DH population of 181 lines was genotyped using the 90K iSelect SNP platform and markers for known genes (Ppd, Vrn, Rht, and FT) that affect plant adaptation. The genotypic data was used in linkage analysis and QTL analysis for yield components and agronomic data using JMP Genomics Software (V9.0). To consider spatial variation, the best linear unbiased prediction (BLUP) was calculated for each trait across all trials. QTL analyses were conducted separately for each trait in individual environments and in trait BLUP across all environments. A total of 48 linkage groups were constructed with a total length of 3892.81 cM and a marker density of 0.33 marker/cM. A total of nineteen QTL were detected, including five for fSNS on chromosomes 5D, 6A, 7B (two QTL), and 7D; two for PTN on chromosomes 4A and 6A; three QTL for TKW on chromosomes 4A, 6A, and 7D; one QTL for GY on chromosome 7D; four QTL for HD on chromosomes 4B, 6A, 7B, and 7D; and four QTL for HT on chromosomes 4A (two QTL), 5D, and 7D. The two parents have complementary and additive QTL effects in all traits evaluated, providing opportunities to improve each trait through pyramiding. However, four QTL, QPTN.uia2-6A, QfSNS.uia2-6A, QTKW.uia2-6A, and QHD.uia2-6A were clustered on chromosome 6A; five other QTL, QTKW.uia2-7D, QfSNS.uia2-7D, QHT.uia2-7D, QGY.uia2-7D, and QHD.uia2-7D were clustered in a small region on chromosome 7DS. The two QTL clusters each control traits that were negatively correlated, suggesting that the trade-off effects pose a challenge and further dissecting of the two clusters is necessary in order to use them in yield improvement. Using the exosome capture data, linkage maps of interest were saturated with additional KASP markers, which helps to dissect the identified QTL clusters. A few of QTL in the two cluster regions were further validated in an elite spring wheat panel, confirming the realty and effectiveness of the identified QTL. KASP markers developed in the present study may useful to pyramid multiple yield components to enhance yield improvement in wheat.
Book Synopsis Genetic Dissection of Stay-green and Other Traits Related to Dry Land Spring Wheat Performance by : Roshan Kumar Acharya
Download or read book Genetic Dissection of Stay-green and Other Traits Related to Dry Land Spring Wheat Performance written by Roshan Kumar Acharya and published by . This book was released on 2016 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spring wheat production in the upper Great Plains is at risk due to increased occurrence of low moisture and high temperatures during grain-fill. Wheat yield is impacted by several often counteracting traits, including seed number per head, seed weight and number of productive tillers. A variety of morphological and phenological plant characteristics impact performance in conditions of low moisture and high temperatures during grain-fill. In this study, we dissect traits associated with grain yield using a recombinant inbred line (RIL) mapping population derived from parents with contrasting phenotypes for several yield and drought related traits. Importantly, differences in quantitative trait loci (QTL) for yield and yield components were observed in the RIL between rain-fed and irrigated environments. We report important QTLs associated with yield and drought stress in spring wheat, with the long term goal of identifying traits useful to molecular breeding programs for the creation of lines better adapted to our changing environments. We also confirmed six grain-fill QTLs in association mapping (AM) panel which were identified by using this RIL population.
Book Synopsis Competitive Effect for Grain Yield of Four Cultivars in Pure and Mixed Populations in Wheat (Triticum Aestivum Vill ; , Host) by : José Antonio Valencia-Villarreal
Download or read book Competitive Effect for Grain Yield of Four Cultivars in Pure and Mixed Populations in Wheat (Triticum Aestivum Vill ; , Host) written by José Antonio Valencia-Villarreal and published by . This book was released on 1979 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concerns regarding maintaining wheat yield per hectare and extending the commercial life expectancy of cultivars grown in the Yaqui Valley of Mexico prompted this investigation. Four genetically diverse spring wheat cultivars were grown in pure stands and in all possible combinations at the Northwest Agricultural Research Center at Ciudad Obregon from 1975 through 1978. The composite populations included: 1) a base pop4lation with equal amounts of seed of each cultivar representing the various combinations which was reconstituted and grown each year, 2) a first derived population which was a random sample obtained at harvest from the previously grown base population and grown in 1976-77 and 1977-78 and 3) a second derived population composed of a random sample of seed obtained from the first derived population and grown in 1977-78. The base, first and second derived populations were also grown simultaneously during the third year of the study so that a direct measure of the competitive ability of the cultivars within the composite could be obtained. Data collected from both the pure stands and composite treatments included: 1) grain yield, 2) number of spikes per unit area, 3) number of spikelets per spike, 4) number of kernels per spike, 5) 100 kernel weight and 6) plant height. Date of flowering was obtained for the 1977-78 growing season only. General and specific competitive ability of each cultivar in the composite combinations were determined for the treatments within and across years. Also, simple phenotypic correlations and path-coefficient analyses were employed to determine the relative importance of the components of yield to the competitiveness of a cultivar when grown in a composite. It was observed in this study that those cultivars with the highest grain yield when grown in pure stands were the most competitive in the composites. There were some cultivar x year interactions for the pure stands; however, the same cultivars either ranked first or second for all three years. One cultivar was consistently the lowest each year. In 1976-77, six of the composite treatments exceeded the highest yielding pure stand treatment. This year coincided with the most adverse growing conditions including a leaf rust infection. Jupateco, a cultivar selected for its leaf rust resistance when the study was initiated, was overcome by the pathogen during the second year of this study and a valid comparison as to the selective pressure of this disease was lost as a consequence. Spikes per unit area and kernel number were the most important components of yield both in contributing to high yield and stability of yield. They were also the most important components of yield in contributing to the selective advantage of certain cultivars in the composites. When generating composites, it is important to select varieties which complement one another in terms of their components of yield. Results from this study strongly suggest that to achieve yield stability through the use of composites, a mixture of cultivars should be made each year as the genetic shift among cultivars within the composites is so rapid that the desired genetic diversity would be lost after the first harvest.
Book Synopsis Drivers, Development, and Impact of Tillering Plasticity Mechanisms for Corn Yield Stability in Kansas Environments by : Rachel Lynn Veenstra
Download or read book Drivers, Development, and Impact of Tillering Plasticity Mechanisms for Corn Yield Stability in Kansas Environments written by Rachel Lynn Veenstra and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Historic breeding efforts in corn (Zea mays L.) have resulted in uniform, single-stalked phenotypes with limited environmental plasticity potential. Therefore, plant density is a critical yield component for corn, as it is unable to successfully compensate for a deficit of grain-bearing shoots. Enhancing corn yield stability across plant densities has potential benefits, particularly considering diverse yield environments and seasonal weather uncertainties due to climate change. Research and actionable information regarding branching ("tillering") utility in corn production are largely unavailable. This is particularly relevant in environments where plant density is typically resource-limited or environments in which the target density is not properly achieved. Therefore, the objectives of this dissertation were to determine the following based on tillered corn phenotypes in a range of environment (E) x management (M) scenarios: 1) the impact of tiller development on corn yields; 2) the plastic extent and relative importance of yield components; 3) the drivers and predictability of corn tiller development; and 4) the effect of tiller expression on biomass accumulation, carbon economy, and subsequent reproductive efficiency. This extensive field study evaluated tiller presence (removed or intact) with two commercial hybrids (P0657AM and P0805AM, Corteva Agriscience, Johnston, IA) in a range of plant densities (25000, 42000, and 60000 pl ha−1) across the state of Kansas. In total, 17 site-years were evaluated - comprised of 9 unique field locations across 3 seasons (2019-2021). Yields were increased or unaffected by greater plant densities and tiller presence. Environments varied in yield responsiveness to tiller density, but plant density was key to maximizing yield. Favorable soil properties and higher photothermal quotient (PTQ) values were important correlates of tiller productivity (Chapter 2). Ear number and kernel number per area were less dependent on plant density with tillered phenotypes. Kernel number remained key to yield stability. Although ear number was less related to yield stability, ear source and type were significant yield predictors, with tiller axillary ears as stronger contributors than main stalk secondary ears in high-yielding environments (Chapter 3). Plant density interactions with cumulative growing degree days (GDD), PTQ, mean minimum and maximum daily temperatures, cumulative vapor pressure deficit (VPD), soil nitrate (NO3), and soil phosphorus (P) were important predictive factors of tiller density - many of these with stark non-limiting thresholds. Out-of-season prediction errors were seasonally variable, highlighting the importance of representative training datasets (Chapter 4). Tiller expression stabilized aboveground biomass across plant densities at the hectare scale. Greater tiller biomass was not correlated with any changes in reproductive efficiency. Additional stem tissue allowed tillered corn phenotypes to accumulate a greater reserve of water-soluble carbohydrates in low plant densities and support main stem remobilization demand (Chapter 5). Overall, tillering in corn presents itself as a potentially useful plasticity mechanism in non-uniform field situations with unexpectedly reduced or inadequate plant densities. While limits to tiller productivity are apparent, the branching ability of modern corn hybrids may lend itself to improving resilience of defensive strategies in water-limited environments. It should be noted that although this study explored a range of environments, severe drought scenarios were not explored. The utility of tillering as a plasticity mechanism in corn remains an area of active study.
Book Synopsis Increasing Yield Potential in Wheat by : M. P. Reynolds
Download or read book Increasing Yield Potential in Wheat written by M. P. Reynolds and published by CIMMYT. This book was released on 1996 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Relationships Among Tiller Number, Spike Number, and Yield of Hard Winter Wheat at Selected Kansas Locations and Effect of Planting Date on Fall and Spring Tillers by : Duane Eldon Thiry
Download or read book Relationships Among Tiller Number, Spike Number, and Yield of Hard Winter Wheat at Selected Kansas Locations and Effect of Planting Date on Fall and Spring Tillers written by Duane Eldon Thiry and published by . This book was released on 1997 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effect of Heat Stress and Auxin Application at Flowering on Grain Yield and QTL Associated with Heat Stress Responses in Wheat (Triticum Aestivum L.) by : Ganegama Lekamge Dhuanuja Neranjalee Abeysingha
Download or read book Effect of Heat Stress and Auxin Application at Flowering on Grain Yield and QTL Associated with Heat Stress Responses in Wheat (Triticum Aestivum L.) written by Ganegama Lekamge Dhuanuja Neranjalee Abeysingha and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reproductive phase of wheat (Triticum aestivum L.) is highly sensitive to high-temperature stress. Temperatures above the growth optimum (23oC) interfere negatively with the reproductive development processes, resulting in poor grain set and yield. Crop adaptation strategies can be used to overcome the negative effects of heat stress on grain yield and can be achieved through genetic modifications and proper agronomic practices. Experiments presented in this thesis test the hypotheses that: 1) heat stress at initial flowering (35 °C for 6 h per day for 6 days) has a negative impact on grain yield and foliar auxin application (4-Cl-IAA, 1μM) has the ability to at least partially negate the negative impact of heat stress, and 2) variation in heat stress response with respect to grain yield among a wheat RIL population will allow for the identification of specific phenotypic traits and quantitative trait loci (QTL) associated with heat stress resistance. First, a controlled environment experiment was conducted to evaluate the Canadian hard-red spring and/or CIMMYTY derived parents of two recombinant inbred line (RIL) populations of wheat for heat resistance and auxin responsiveness; the first population was derived from a cross between 'Attila' and 'CDC Go', and the second between 'CDC Teal' and 'CDC Go'. The 'Attila' x 'CDC Go' RIL population (171 lines) was selected for in-depth evaluation because 1) grain yield after heat-stress differed in 'Attila' and 'CDC Go', 2) the ability of a one-time foliar 4-Cl-IAA application (prior to heat stress) to ameliorate the negative effects of heat stress with respect to grain yield was observed in 'Attila' and 'CDC Go', and 3) the 'Attila' × 'CDC Go' RIL population was more extensively characterized in the field in previous studies than the 'CDC Teal' x 'CDC Go' RIL population. The 'Attila' x 'CDC Go' RILs, the parental RIL cultivars, and seven other Canadian spring wheat cultivars were further evaluated for heat resistance and auxin responsiveness under controlled environmental conditions. 'Attila' showed greater yield stability under heat stress conditions at flowering compared to 'CDC Go'. The lower heat tolerance for 'CDC Go' when exposed to the heat stress treatment was reflected in substantial reduction in main tiller grain yield (~ 45%) associated with reductions in the number of fertile spikelets per spike, grains per spikelet and per fertile spikelet. Heat stress reduced the RIL population mean grain number and weight with a substantial reduction in fertile spikelets per spike and grain number per spikelet or per fertile spikelet. Within the RIL population, 45% (77 RILs) were categorized as heat-resistant, 20.5% as moderately heat susceptible (35 RILs) and 7.6% (13 RILs) as highly heat susceptible with respect to grain weight. Strong to minor relationships were observed between yield component traits and grain yield among the standard spring wheat cultivars and the 'Attila' × 'CDC Go' RIL population, and in some cases heat stress affected the strength of the relationships. Auxin treatment increased some yield traits (grain number and weight, fertile spikelets per spike, and grain number per spikelet or per fertile spikelet) under heat stress and/or non-temperature stress conditions in 'Attila', 'CDC Go', and RILs 18, 46, 70, 80, and 145. Inclusive composite interval QTL mapping was conducted using phenotypic data of the 'Attila' x 'CDC Go' RIL population and genotypic data obtained from a previous study conducted using a subset of (1200 SNPs) Wheat 90K SNP array together with Ppd-D1, Vrn-A1, and Rht-B1 genes. Whole spike and spike section data from non-temperature stress (NS) and heat stress (HS) treatments identified 73 QTL (NS, 37; HS, 36) on 14 of the 21 chromosomes (1A, 1B, 2A, 2B, 2D, 3A, 4A, 4B, 5A, 5B, 6A, 6B, 7B, 7D) that individually explained 1.6 to 47.5% phenotypic variation with Logarithm of Odds (LOD) values ranging from 2.5 to 25.8. Eight important QTL clusters associated with two or more important grain yield or yield-related traits were identified on chromosomes 5A, 4B, 2B, 2D and 1B. Overall, heat stress at early flowering reduced grain yield, with the magnitude of the reduction dependent on the genotype. Relationships between grain yield and other yield-component traits were modified by the heat stress in some cases, stressing the importance of cultivar trait evaluation under environments where the cultivar will be grown. One-time foliar application of auxin prior to heat stress (4-Cl-IAA at 1 μM) at the early flowering stage can increase the grain yield and/or yield component traits in some genotypes and has the potential for use as an agronomic tool to enhance wheat grain yield. QTL and QTL clusters were identified for non-temperature stress and/or heat stress, with many detected in QTL hotspots in the wheat genome for grain yield and spike architecture.
Book Synopsis The Impact of Conservation Tillage Technology on U.S. Wheat Productivity Growth and Regional Competitive Advantage by : Stephen C. Cooke
Download or read book The Impact of Conservation Tillage Technology on U.S. Wheat Productivity Growth and Regional Competitive Advantage written by Stephen C. Cooke and published by . This book was released on 1991 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Halophytes for Food Security in Dry Lands by : Muhammad Ajmal Khan
Download or read book Halophytes for Food Security in Dry Lands written by Muhammad Ajmal Khan and published by Academic Press. This book was released on 2015-09-15 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: Halophytes for Food Security in Dry Lands addresses the concerns surrounding global food scarcity, especially focusing on those living in arid and dry lands The book touches on food crises in dry regions of the world and proposes halophytes as an alternate source of consumption for such areas. Halophytes, those plants that thrive in saline soil and provide either food source options themselves, or positively enhance an eco-system’s ability to produce food, and are thus an important and increasingly recognized option for addressing the needs of the nearly 1/6 of the world’s population that lives in these arid and semi-arid climates. Including presentations from the 2014 International Conference on Halophytes for Food Security in Dry Lands, this book features insights from the leading researchers in the subject. It is a valuable resource that includes information on the nutritional value of halophytes, their genetic basis and potential enhancement, adaption of halophytes, and lessons learned thus far. Provides comprehensive coverage of the importance and utilization of halophytes to compensate the demand of food in whole world especially in the dry regions Contains insights from ecological to molecular fields Includes edible halophytes as well as those that enhance food-producing eco-systems Presents information for improving abiotic stress tolerance in plants
Book Synopsis Combining Ability and Associations of Agronomic Traits Involving Three Sources of Dwarfism in Wheat (Triticum Aestivum, L. Em Thell) by : Jose Luis Maya de Leon
Download or read book Combining Ability and Associations of Agronomic Traits Involving Three Sources of Dwarfism in Wheat (Triticum Aestivum, L. Em Thell) written by Jose Luis Maya de Leon and published by . This book was released on 1974 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three genetically different dwarf cultivars of spring wheat were evaluated as potential sources of short stature to use in a wheat improvement program. The study involved a five parent diallel cross which included a semidwarf, a standard height and three dwarf cultivars. The genetic sources of dwarfism included a Norma 10 derivative named Vicam 71, a derived line from Tom Thumb called Tordo, and Olesen dwarf. Experimental material consisted of parental lines, F1, F2, and both backcrosses to the parents space planted in a randomized block design. The agronomic characters measured on an individual plant basis were: (1) plant height, (2) days to heading, (3) number of tillers, (4) number of spikelets per spike, (5) head length, (6) days to maturity, (7) grain yield, (8) harvest index, (9) kernel weight, (10) number of kernels per spikelet, (11) rachis internode length, (12) grain filling period and, (13) head grain weight. Estimates of gene action were determined by heterosis, heterobeltiosis, broad and narrow sense heritabilities and combining ability analyses. Associations among traits were estimated by phenotypic, environmental, and genotypic correlations as well as path-coefficient analysis for grain yield and eight of the variables. There were significant differences among the parental lines, their crosses, and generations for all traits measured. Either partial dominance for tallness or no dominance was manifested for those crosses involving the dwarf cultivars Vicam 71 and Olesen. Tordo, when crossed to taller wheats showed dominance for short stature. All three genetic sources of dwarfism and their resulting progenies manifested desirable agronomic characteristics. Vicam 71 was a good parent in terms of grain yield and number of tillers per plant. Tordo was the best source for increasing the number of spikelets per spike, kernel weight and head grain weight. Olesen was a good progenitor for increasing number of kernels per spikelet. All three dwarf cultivars displayed some advantage(s) over the other two and all could be used to breed short statured wheats with a possibility of success. Plant height did not appear to have a direct effect on plant grain yield in any of the 10 crosses. With the exception of number of tillers per plant and grain yield, a major proportion of the phenotypic variability observed for all characters studied was due to genetic factors. A large portion of the total genetic variability associated with days to heading, maturity, height, rachis internode, spikelet number, kernels per spikelet, kernel weight, and harvest index was mainly a result of additive gene action. Both additive and non-additive genetic effects were involved in the expression of grain filling period and head weight. The nonadditive portion of the genetic variance associated with tiller number and grain yield per plant was relatively large when compared with the additive portion. Therefore, selection for increased expression of tillers and yield should be delayed until the F4 or later generations where a large degree of homozygosity has been obtained. The genetic correlations for individual crosses indicated that only a few of the traits studied were associated in the same manner in most or all the 10 hybridizations. High positive genetic correlations were found between plant grain yield vs tiller number and kernels per spikelet, tiller number vs days to maturity, kernels per spikelet vs head grain weight, plant height vs head weight, and head length vs rachis internode length. High negative genetic correlations were found between kernel weight vs days to maturity, plant height vs harvest index, and days to heading vs grain filling period. Most correlations among agronomic traits were different in value and/or sign from one cross to another suggesting different gene associations in the parental cultivars. Genetic correlations between components of yield showed this type of inconsistency. Therefore, grain yield could be increased by a combined increase of more than one component of yield without compensatory oscillation among them because tiller number, spikelet number, kernels per spikelet and kernel weight were often not correlated between one another and sometimes were positively correlated. Path-coefficients analysis indicated that number of tiller per plant had a high direct effect on grain yield in all crosses. With the exception of two crosses, indirect effects of this trait were negligible. In the latter two crosses tiller number had a high negative indirect effect on plant grain yield via head grain weight. Kernels per spikelet and kernel weight had no direct effects on grain yield but their indirect effects via head weight were positive and significant. Large amounts of additive gene action were observed in the expression of plant height. This trait was also highly negatively correlated with harvest index; therefore, phenotypic selection for restricted plant height would be useful in obtaining lines with high grain to straw ratios. In general, crosses that showed high specific combining ability effects involved parents with low general combining ability. However, there were some exceptions to this rule. Crosses of high x high and high x low general combiners presented high specific combining ability effects, suggesting that some additive gene action may be involved in the superior performance of these combinations. Also the F 2 generation did not differ from the F1 in assessing general cornbining ability. A wheat breeder should be aware of those genetic associations between agronomic traits that could be used to select superior cultivars. However, the genetic correlations in this study suggested that each cross represented a different set of gene associations depending upon the parents involved. If some progress is to be made in using the genetic variability available in the crop, the breeder should not try to select exactly the same type of plant from every cross. Every hybridization is potentially a source of better lines if they are well planned and the reasons they were made are remembered during selection. It is very important to realize what are the contributions of each parental line in a cross and what are the most important trait associations present in each parent. Superior rural genetic variability existing in the crop.
Book Synopsis Quantitative Trait Loci Associated with Waterlogging Tolerance in a Soft Red Winter Wheat by : Diana Carolina Ballesteros Benavides
Download or read book Quantitative Trait Loci Associated with Waterlogging Tolerance in a Soft Red Winter Wheat written by Diana Carolina Ballesteros Benavides and published by . This book was released on 2013 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Waterlogging is caused when water stays superficially in the soil for an extended period of time, creating an anaerobic environment which decreases plant growth and grain yield at maturity. Despite the impact of waterlogging on wheat production both globally and in the southeastern U.S., very little is known about the genetic control of waterlogging tolerance in wheat. The objective of this study was to determine the amount of genetic variation for vegetative stage waterlogging tolerance present within a wheat recombinant inbred line (RIL) population and to identify quantitative trait loci (QTL) associated with tolerance and productivity. Experiments were carried out in both the greenhouse and the field using a RIL population derived from the wheat cultivars 'USG3209' and 'Jaypee'. The effect of vegetative stage waterlogging was determined by quantifying fresh shoot biomass, fresh root biomass, dry shoot biomass, dry root biomass, root length, chlorophyll content, tiller number, elongation, and plant height pre and post-treatment under stressed and non-stressed conditions. In both the greenhouse and the field experiments, biomass traits, chlorophyll content ere significantly reduced by waterlogging stress with percent reduction ranging from 10 to 54%. Significant genetic variation was detected for biomass traits, chlorophyll content, tiller number, elongation, and plant height post-treatment. Root traits showed high sensitivity to waterlogging and significant genotype by treatment interaction. Shoot biomass and root biomass were highly correlated, indicating the possibility of indirect selection for root biomass. The QTL analysis revealed 53 total QTLs, with 34 detected under waterlogging stress. These QTLs clustered into 19 regions distributed throughout the wheat genome. QTL on chromosomes 2A, 2B, 2D, 5A and 5B were found to localize with known genes regulating plant height and flowering time. Other QTL regions located on chromosomes 1B, 2A and 6B appear to be novel for biomass production specific to waterlogging stress and can be used for marker-assisted selection to more efficiently select for waterlogging tolerant lines.
Book Synopsis Crop Stress and its Management: Perspectives and Strategies by : B. Venkateswarlu
Download or read book Crop Stress and its Management: Perspectives and Strategies written by B. Venkateswarlu and published by Springer Science & Business Media. This book was released on 2011-11-22 with total page 617 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crops experience an assortment of environmental stresses which include abiotic viz., drought, water logging, salinity, extremes of temperature, high variability in radiation, subtle but perceptible changes in atmospheric gases and biotic viz., insects, birds, other pests, weeds, pathogens (viruses and other microbes). The ability to tolerate or adapt and overwinter by effectively countering these stresses is a very multifaceted phenomenon. In addition, the inability to do so which renders the crops susceptible is again the result of various exogenous and endogenous interactions in the ecosystem. Both biotic and abiotic stresses occur at various stages of plant development and frequently more than one stress concurrently affects the crop. Stresses result in both universal and definite effects on plant growth and development. One of the imposing tasks for the crop researchers globally is to distinguish and to diminish effects of these stress factors on the performance of crop plants, especially with respect to yield and quality of harvested products. This is of special significance in view of the impending climate change, with complex consequences for economically profitable and ecologically and environmentally sound global agriculture. The challenge at the hands of the crop scientist in such a scenario is to promote a competitive and multifunctional agriculture, leading to the production of highly nourishing, healthy and secure food and animal feed as well as raw materials for a wide variety of industrial applications. In order to successfully meet this challenge researchers have to understand the various aspects of these stresses in view of the current development from molecules to ecosystems. The book will focus on broad research areas in relation to these stresses which are in the forefront in contemporary crop stress research.
Book Synopsis Symposium on Breeding for Diversification by : Jelena Ba?anovi?-Šiši?
Download or read book Symposium on Breeding for Diversification written by Jelena Ba?anovi?-Šiši? and published by kassel university press GmbH. This book was released on 2018-02-26 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: We are very happy that in this symposium researchers from a multitude of countries around the world are coming together in order to discuss issues about breeding for intra- and inter-specific diversity as well for annuals as for perennials. THe submitted abstracts show that the activities are far wider than just the cereals that are covered by the EU directive and that there will be a need to expand the activities on the legal side.
Book Synopsis Selection Methods in Plant Breeding by : Izak Bos
Download or read book Selection Methods in Plant Breeding written by Izak Bos and published by Springer Science & Business Media. This book was released on 2013-11-21 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our requirement for plant breeders to be successful has never been greater. However one views the forecasted numbers for future population growth we will need, in the immediate future, to be feeding, clothing and housing many more people than we do, inadequately, at present. Plant breeding represents the most valuable strategy in increasing our productivity in a way that is sustainable and environmentally sensitive. Plant breeding can rightly be considered as one of the oldest multidisciplin ary subjects that is known to humans. It was practised by people who first started to carry out a settled form of agriculture. The art, as it must have been at that stage, was applied without any formal underlying framework, but achieved dramatic results, as witnessed by the forms of cultivated plants we have today. We are now learning how to apply successfully the results of yet imperfect scientific knowledge. This knowledge is, however, rapidly develop ing, particularly in areas of tissue culture, biotechnology and molecular biology. Plant breeding's inherent multifaceted nature means that alongside obvious subject areas like genetics we also need to consider areas such as: statistics, physiology, plant pathology, entomology, biochemistry, weed science, quality, seed characteristics, reproductive biology, trial design, se lection and computing.
Author :Food and Agriculture Organization of the United Nations Publisher :Food & Agriculture Organization of the UN (FAO) ISBN 13 : Total Pages :576 pages Book Rating :4.3/5 (91 download)
Book Synopsis Bread Wheat by : Food and Agriculture Organization of the United Nations
Download or read book Bread Wheat written by Food and Agriculture Organization of the United Nations and published by Food & Agriculture Organization of the UN (FAO). This book was released on 2002 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wheat is the most widely grown cereal crop in the world, with an ever increasing demand. It plays a fundamental role in food security, and a major challenge is to meet the additional requirements with new cultivars and improved cropping technologies. This book covers information from a number of international experts on the current status of research on wheat improvement and production (wheat breeding programs and genetics), as well as on other aspects (including wheat diseases), from its evolutionary origins to seed production technologies. [from the FAO website]
