Genotypic Variability for Agronomic and Physiological Traits in Sorghum (Sorghum Bicolor [L.] Moench) with Optimum and Suboptimum Water Levels PDF Download

Author: Abdalla I. Sheikh-Mohamed
Publisher:
ISBN:
Category : Plants
Languages : en
Pages : 106

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Author:
Publisher:
ISBN:
Category : Agriculture
Languages : en
Pages : 622

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Sept.-Oct. issue includes list of theses and dissertations for U.S. and Canadian graduate degrees granted in crop science, soil science, and agronomic science during the previous academic year.

Author: Sebastine Obi Onwuka
Publisher:
ISBN:
Category : Irrigation water
Languages : en
Pages : 78

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Author: C.P. Camargo
Publisher:
ISBN:
Category :
Languages : en
Pages : 74

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Seed of 36 sorghum (Sorghum bicolor (L.) Moench) geneotypes selected on the basis of high physiological quality were evaluated to determine genotypic differences in response to germination temperatures ranging from 10 to 42C. Seed of high, medium, and low quality were evaluated to investigate seed quality-germination-tempearture relationships. Seed of 24 genotypes were dimensionally sized and permitted to imbile water to evaluate both genotypic variation in speed of water uptake and the influence of seed size on water imbibition. Sorghum seed of near maximum phusiological quality germinated equally well at temperatures between 20 and 30C. Among the range of genotypes evaluated, constant germination temperatures of 14 and 42C were the best for screening genotypes for their to germinate at low and high temperatures, respectively. Two genotypes, IS 1166C and SC 175-14, were equal to or better than all other genotypes at all germination temperatures evaluated. Five genotypes, E 35-1, MN 1958, MN 4508, IS 12685C and TPDXB1388 (9256) were very sensitive to germination temperatures outside the optimal range. Seed of lower physilogical quality were more sensitive to germination temperatures than those of high quality. However, there was a differential response among the genotypes. Regardless of genotype, small seed increased in moisture content more rapidly than large seed when water supply was not limited. Within the same size. there was genotypic varation both in the rate of moisture absorption and the time (...).

Author: Cilas Pacheco Camargo
Publisher:
ISBN:
Category : Germination
Languages : en
Pages : 148

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Author: Malik Muhammad Khan
Publisher: LAP Lambert Academic Publishing
ISBN: 9783847343400
Category :
Languages : en
Pages : 80

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Drought is the most common adverse environmental condition that can seriously reduce crop productivity. Increasing crop resistance to drought stress would be the most economical approach to improve agricultural productivity and to reduce agricultural use of fresh water resources. As a result, understanding the drought tolerance and breeding for drought resistant crop plants has been the major goal of plant breeders. Sorghum is well-known for its capacity to tolerate conditions of limited moisture and to produce during periods of extended drought. Twenty sorghum (Sorghum bicolor L. Moench) genotypes with known drought tolerance traits were used in this study. The present study will be conducted to evaluate the genetic variability for drought tolerance in sorghum genotypes at molecular level.

Author: C.L.Narasimha Rao
Publisher:
ISBN:
Category :
Languages : en
Pages : 159

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Author: V. B. Ogunlela
Publisher:
ISBN:
Category :
Languages : en
Pages : 203

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Two greenhouse and three field experiment were conducted to study the effects of elevated night temperatures on the yield and growth of a grain sorghum (Sorghum bicolor (L.) Moench) hybrid. The genotype used in these investigations was the 'RS 671' (Redlan x Tx 415), an open-pedigree temperate-adapted grain sorghum. The phenological growth phase during which temperature treatments were imposed was the panicle development (GS-2) period. Experiment I, II (greenhouse) and III (field) were designed to determine the response of grain sorghum to two elevated night temperatures and the growth stage during GS-2 period when the plant is most sensitive to elevated temperatures. Experiment IV and V (field) were conducted with the same objectives as those for Experiment I, II and III and also to determine the effects of artificial preconditioning on the plant's response to elevated night temperatures. Experiments I - Plants were exposed to 26.5 and 32 C night temperatures at 4-day durations commencing from florest differentiation through bloom. The two elevated night temperatures caused significant reduction in grain yield and yield components except seed size that was enhanced (12%) by the 32 C treatment. Approximately 19%, 21%, 24% and 20% reductions in panicle dry weight, grain yield per plant, number of seeds per panicle and grams of grain/GS-3 day/plant, respectively, were caused by the 32 C treatment. The 26,5 C treatment also caused reduction in these variables but to much lesser degrees. Numbers of days to (...).

Author: ASHVATHAMA V. H
Publisher:
ISBN:
Category :
Languages : en
Pages : 144

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Author: Frank Maulana
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The approach used to identify inbred lines that can produce superior hybrids is costly and time-consuming. It requires creation of all possible crosses and evaluation of the crosses to estimate combining abilities for the desired traits. Predicting heterosis or hybrid performance in any way possible may help to reduce the number of crosses to be made and evaluated. In this study, four sets of experiments were conducted to determine whether heterosis can be predicted based on inbred line performance, genetic distance between parents and genomic prediction model. The first experiment was aimed at assessing the levels of genetic diversity, population structure and linkage disequilibrium (LD) in 279 public sorghum inbred lines, based on 66,265 SNPs generated using the genotyping-by-sequencing (GBS) platform. The inbred lines were developed at different times over the last two decades and harbor robust diversity in pedigree and agronomic characteristics. Some of the inbreds are resistant to Acetolactate synthase (ALS) and Acetyl co-enzyme-A carboxylase (ACC) inhibitor herbicides. The mean polymorphic information content (PIC) and gene diversity across the entire inbreds were 0.35 and 0.46, respectively with non-herbicide resistant inbreds harboring more diversity than the herbicide resistant ones. The population structure analysis clustered the inbred lines into three major subgroups according to pedigree and fertility-reaction with the maintainer lines (B-lines) distinctly forming a separate cluster. Analysis of molecular variance (AMOVA) revealed more variation within subgroups than among subgroups. Substantial linkage disequilibrium (LD) was detected between the markers in the population with marked variation between chromosomes. This information may facilitate the use of the inbreds in sorghum breeding programs and provide perspectives for optimizing marker density for gene mapping and marker-assisted breeding. The second experiment, based on 102 F1 hybrids developed by intercrossing closely and distantly related inbreds, was conducted to investigate the relationship of genetic distance between parents with hybrid vigor or heterosis. The F1 hybrids alongside their parents were evaluated at two environments in a randomized complete block design with three replications. The results show that correlations of genetic distance between parents with hybrid performance and heterosis were variable and dependent on the trait. Though most were statistically non-significant and not strong to be used as predictor for heterosis, the results tend to show that certain level of genetic distance between parents is needed to capture maximum heterosis and hybrid performance. The objective of the third research study was to determine whether traits measured on parents can be used to predict hybrid performance in sorghum and to assess the combining ability of selected inbreds. Forty-six parental inbred lines and 75 F1 hybrids generated from intercrossing the inbreds were evaluated in four environments in a randomized complete block design with three replications. The average performance of the parents (mid-parent) was significantly correlated with hybrid performance for thousand kernel weight, days to flowering and plant height. Significant general (GCA) and specific (SCA) combining abilities were observed for most traits, with highly significant GCA effects observed for most traits as compared to SCA indicating that additive genetic effects are more important in affecting the inheritance of the traits measured. Results show that studying parental inbred line performance could generate important information for predicting hybrid performance in sorghum. The fourth experiment was aimed at assessing the efficacy of genomic prediction of hybrid performance in sorghum. Genomic prediction was performed with five-fold cross-validation procedure on 204 F1 hybrids developed using 102 inbred lines. A total of 66,265 SNP markers generated using genotyping-by-sequencing were used in this study. Results showed that increasing training population size increased prediction accuracies for all traits with the effect being different for different traits. Also, considering additive effects alone versus additive and dominance effects in the model showed similar trend of prediction accuracy but the full model (considering both additive and dominance effects of the markers) provided better prediction at least for some of the traits. The results suggest that genomic prediction could become an effective tool for predicting the performance of untested sorghum hybrids thus adding efficiency to hybrid selection.