Inheritance Of Agronomic Traits Research Articles

Inheritance studies on grain iron and zinc concentration and agronomic traits in sorghum [Sorghum bicolor (L.) Moench

Sorghum is a major staple globally and biofortifying sorghum with increased grain iron and zinc complements ongoing efforts to combat micronutrient malnutrition. Limited information available on the nature and magnitude of gene effects for grain iron and zinc. So generation mean analysis was done using four crosses, ICSB 52 × IS 13211, ICSB 52 × SPV 1359, IS 20843 × IS 2248 and IS 2248 × IS 20843. Six generations, P1, P2, F1, F2, B1 and B2, were generated for each of these crosses which were evaluated during the postrainy season 2012–13. The mean sum of squares due to generations were significant for days to flowering, plant height, grain yield/plant, 100-grain weight, and grain Fe and Zn. Generation mean studies revealed the presence of both additive and dominant gene interactions in inheritance of agronomic traits. Duplicative epistasis was observed for days to flowering, plant height, grain yield/plant, 100-grain weight, and grain Zn with a predominance of dominant gene action in inheritance of these traits. Panicle length, panicle width, and grain Fe showed both additive and dominance gene effects, with higher magnitude of dominance. This information can be utilized in developing sorghum lines with high grain Fe and Zn.

Genetic Control and Heterosis of Quantitative Traits in Several Local Eggplant Genotypes

The present study was performed to assess the nature of gene action governing inheritance of agronomic traits in eggplant genotypes and extent of mid parent heterosis (MPH) and better parent heterosis (BPH) in six eggplant hybrids generated from four superior and optimally divergent genotypes of eggplant namely ‘Yalo’, ‘Uyo’, ‘K3’ and ‘Iyoyo’ selected from the germplasm and were crossed in 4×4 half diallel mating design. The six hybrids were found to show a significant (p< 0.05) positive MPH in yield traits and the highest was obtained in the hybrid ‘Yalo’ × ‘K3’ for number of fruits per plant (158.90%) and ‘K3’ × ‘Iyoyo’ for fruit yield per plant (63.14%) and fruit yield per hectare (62.20 %). The hybrid combinations ‘Yalo’ × ‘K3’ and ‘K3’ × ‘Iyoyo’ had significant positive BPH for the number of fruits per plant, 104.08% and 42.43%, respectively. For fruit yield per plant, the hybrid combination ‘Yalo’ × ‘K3’ (7.93%), ‘Uyo’ × ‘K3’ (8.48%) and ‘K3’ × ‘Iyoyo’ (12.26%) had significant positive BPH. However, the hybrid ‘K3’ × ‘Iyoyo’ (11.51%) showed significant positive BPH in fruit yield per hectare. Dominance and dominance × dominance gene effect were found to be positively higher in magnitude in all crosses for number of fruits per plant, fruit yield per plant and fruit yield per hectare. The prevalence of dominance and dominance × dominance gene effect in the yield traits indicate heterosis breeding as the best breeding method to improve the productivity of eggplant.

ПЕРСПЕКТИВЫ И РЕЗУЛЬТАТЫ ИЗУЧЕНИЯ КОЛЛЕКЦИИ НУТА В ОМСКОМ ГАУ

In 2012-1016, 23 chickpea accessions from VIR and 23 accessions from the collection of chickpea somaclones of the Siberian Research Institute of Forages were studied at Omsk State Agrarian University. The research performed in the southern forest-steppe of West Siberia resulted in identifying chickpea accessions with a shorter growing season, high plant productivity, good processability, and high symbiotic activity. The possibility of using cluster analysis for comprehensive assessment of source material for chickpea breeding was demonstrated. The nature of inheritance of agronomic traits in F1 chickpea hybrids was revealed, and recommendations for selection were formulated. A correlation was established between the major characters.

Within-family genetic variation and epistasis in cassava (Manihot esculenta Crantz) adapted to the acid-soils environment

Little is known about the inheritance of agronomic traits in cassava, or on the relative importance of epistasis for most crops. A group of 10 clones, adapted to the acid-soils environment was used as parents in a diallel study. Thirty genotypes were obtained from each F1 cross and cloned. Each clone was represented by six plants, which were distributed in three replications at two contrasting locations. Genetic variability concentrated in the within-family component, which was statistically significant for all the variables analyzed (fresh root yield (FRY), fresh foliage yield (FFY), harvest index, root dry matter content, and plant type score (PTS)) except for the reaction to super elongation disease (SED). Estimates of dominance variance were considerably larger than those of additive variance for fresh root and foliage yields. The reverse was observed for harvest index, dry matter content, PTS and SED score. Epistasis played an important role only for fresh root and foliage productions. These results agree with those from similar studies targeting different environments. The common assumption of absence of significant epistatic effects frequent in many quantitative genetic designs is, therefore, challenged from the results for these two variables. Alternative breeding approaches are suggested according to the results obtained from this study.

Epistasis in the Expression of Relevant Traits in Cassava (Manihot esculenta Crantz) for Subhumid Conditions

There is limited knowledge on the inheritance of agronomic traits in cassava and the importance of epistasis for most crops. A nine-parent diallel study was conducted in subhumid environments. Thirty clones were obtained from each F1 cross. Each clone was represented by six plants, which were distributed in three replications at two locations. Therefore the same 30 genotypes of each F1 cross were planted in the three replications at the two locations. Analysis of variance suggested significant genetic effects for all variables analyzed (reaction to thrips, fresh root and foliage yields, harvest index, dry matter content, and root dry matter yield). Significant epistatic effects were observed for all variables, except harvest index. Dominance variance was always significant, except for dry matter content and dry matter yield. Additive variance was significant only for reaction to thrips. Results suggested that dominance plays an important role in complex traits such as root yield. The significance of epistasis can help us understand the difficulties of quantitative genetics models and QTLs in satisfactorily explaining phenotypic variation in traits with complex inheritance. Significant epistasis would justify the production of inbred parental lines to fix favorable allele combinations in the production of hybrid cassava cultivars.

Epistasis in Cassava Adapted to Midaltitude Valley Environments

Little is known about the inheritance of agronomic traits in cassava (Manihot esculenta Crantz). The vegetative multiplication of cassava allows cloning of individual genotypes, and separates environmental from genetic variation in the within‐family variation. Knowing the magnitude of between‐ and within‐family variation is important for defining breeding strategies and for measuring different components of genetic variances, particularly the seldom‐estimated epistasis. A group of nine genotypes, adapted to midaltitude environments, was used for a diallel study. Thirty clones were obtained from every F1 cross (each clone was represented by six plants), and planted in three replications at two locations. Statistical differences among crosses were found for fresh‐root yield, harvest index, root dry‐matter content, and reaction to mites (Mononychellus tanajoa Bondar) and to whiteflies (Aleurotrachelus socialis Bondar). General combining ability (GCA) was significant for all traits except fresh‐root yield and dry‐matter content, and specific combining ability (SCA) was significant for all traits except whitefly damage score. Fresh‐root yield was the only trait with significant epistatic effects, which, combined with a large dominance variance, suggested a prevalence of nonadditive effects. The introduction of inbreeding would be one approach for the efficient exploitation of these nonadditive effects found for fresh‐root yield. For the remaining traits, epistasis was negligible and current schemes exploiting additive effects may suffice.

Inheritance of agronomic traits from the Chinese barley dwarfing gene donors 'Xiaoshan Lixiahuang' and 'Cangzhou Luodama'

The inheritance of agronomic traits from the barley dwarfing gene donors ‘Xiaoshan Lixiahuang’ and ‘Cangzhou Luodamai’ was studied. The results indicated that dwarf plants, six-row and short spikes, dense spikelets and naked kernels, respectively, were controlled by one pair of recessive genes, but a toothed awn was determined by one pair of dominant genes in both barley cultivars. The genes for the six characters in ‘Xiaoshan Lixiahuang’ were allelic to those in ‘Cangzhou Luodamai’. Genetic linkage was found among the genes for plant height, spike length and spikelet density. They were located on the long arm of chromosome 3 (3HL) in the order: plant height, spikelet density, spike length. The genes for naked kernels, six-row spikes and tooth awns were independent of each other, and carried on the long arms of chromosomes 1(7H), 2(H) and 7(5H), respectively. The dwarfing genes were the same as the gene uz in Japanese and Korean barley cultivars.

Optimisation of breeding for agronomic traits in fibre hemp (Cannabis sativa L.) by study of parent-offspring relationships

In the framework of a comprehensive Dutch research project the feasibility of hemp cultivation for paper pulp production is being investigated. This project also includes a hemp breeding programme which was initiated at CPRO-DLO in 1990. Hemp breeding is primarily aimed at improving bast fibre production since bast fibre is qualitatively superior to woody core fibre for paper pulp production. The progress of the ongoing breeding programme is hampered by the lack of knowledge on the inheritance of agronomic traits.

Detection of Epistatic, Additive, and Dominance Variation in Winter Wheat (Triticum aestivum L. em Thell.)1

The objectives of this study were to determine whether epistasis plays a significant role in the genetic systems for selected traits among several winter wheat (Triticum aestivum L. em Thell.) cultivars and to evaluate the importance of additive vs. dominance gene action for traits not influenced by epistasis. In each of two replicated experiments, two cultivars (referred to as testers L1 and L2) and their F1 (L3) were crossed to each of 10 other cultivars and evaluated in a single field experiment. The deviations (cultivar ✕ L1 + cultivar ✕ L2 — 2 cultivar ✕ L3) were analyzed to provide a test for epistasis. An additive‐lominance model was fitted to the data for those characters not affected by gene interactions.Results of the two experiments were generally consistent with respect to the detection of epistasis. Epistasis affected the expression of heading date, kernels/spikelet, and grain yield, but not of plant height, protein content, tiller number, spikelets/spike, and kernels/spike in both experiments. Epistasis was indicated for kernel weight in one experiment but not the other. Expression of epistasis was influenced by particular cultivars, indicating that a limited number of cultivars may not be sufficient to detect nonallelic interactions for a character within this species.Additive gene action was predominant in both experiments for protein content, spikelets/spike, and kernels/spike, suggesting that improvement of those characters can be achieved through standard selection procedures. Evidence for dominance gene action was obtained for plant height and kernels/spike in one experiment.The results of this study indicated that epistasis may be a nontrivial factor in the inheritance of agronomic traits. Genetic models neglecting epistasis may result in biased information.

Analysis of tomato agronomic traits using generation mean

Information on inheritance of agronomic traits and lack of tomato (Solanum lycopersicum L.) a robust breeding programme in Kenya, has led to dependency on imported tomato varieties. The objective of this study was to assess the inheritance of growth attributes of tomato lines in Kenya and identify cross family with great potential for further breeding. Six generations; namely P1, P2, F1, F2, BC1P1 and BC1P2‚ were developed from five parental lines. A split-plot design with crosses as main plots and generations as subplots was used in two sites (Kabete Field Station and Mwea Research Station), located in Kenya. Cross Roma VF x AVTO1424 and Roma VF x AVTO1314 were the earliest (33 days) to reach 50% flowering; while BC1P2‚ of Roma VF (38 days) was the latest to flower. Mwea Station had plants with the tallest plants, with a mean height of 62 cm at 50% flowering, compared to Kabete Station with a mean height of 48 cm. A significant increase (>10%) in plant height was registered in F1 generations compared to parental lines. Plant height at maturity across the environments ranged from 82 cm for shorter parent, Roma VF, to 120 cm for taller offspring BC1P1. Significant genotype x environment interactions were observed in Roma VF x AVTO1314 and Roma VF x AVTO1429 for days to 50% flowering, plant height, and number of trusses per plant. The importance of gene effects for agronomic trait inheritance was in additive and dominance-additive portions, which implied that traits were inherited.