Line × tester Study in Bread Wheat (Triticum aestivum L.) for Important Biochemical and Morphological Traits

: Using line × tester analysis, the current research analyses parental genotypes and their combinations in normal conditions and identifies the genes influencing yield characteristics. In the present study, 15 diverse genotypes, including 10 lines, 5 testers, and 50 F1s hybrids, were evaluated for 13 morphological and 2 biochemical traits. A suitable location was taken to study the effect of 15 characters. The results exposed that ability mean squares were significant for all studied additive and non-additive components. In this direction, the general combining ability of PBW-343, DBW-39, K-402, K-1317, KRL-210, and K-68 were higher than the remaining parents. For morphological traits like yield, the top five crosses were described based on SCA effects, namely, HD-3086 × HD-3171, K-402 × K-9107, K-1317 × K-9107, HD-2967 × K-0307 and K-402 × K-68 in F1 generation. In addition, the high value of heritability was estimated for plant height (77.32%), spike length (32.26%), biological yield/plant (59.52%), and grain yield/plant (68.76%). However, the moderate values of heritability were estimated for days to maturity (22.78%) and phenol color reaction (18.00%). The higher genetic advance was not found for recorded characters; however, a moderate genetic advance was recorded for grain yield per plant (13.15%) and harvest index (11.72%). High heritability coupled with moderate genetic advance was recorded for two characters grain yield per plant and harvest index in F1 and F2 generations.

Elucidation of Genetic Parameters Controlling Yield and Quality Traits in Rice (Oryza sativa L.)

Background: Forty two crosses involving seven lines and six testers were studied for economically important yield contributing and quality traits to test the magnitude of genetic components and diversity. Formulation of efficient breeding methodology is possible by targeting the genetic architecture of genotypes. Methods: The systematic breeding programme involves generating genetic variability besides sorting off the diverse genotypes and utilizing the extreme phenotypes for producing stable varieties. Genetic diversity helps to achieve the greater continuum of genetic variability in segregating populations to reach for ideal selection of progenies. Heritability and genetic advance are other important selection parameters for retrieving better genotype through selection. Result: Significant differences in analysis of variance were recorded for all the traits. The results signified the greater value of phenotypic coefficient of variation (PCV) than genotypic coefficient of variation (GCV) and environment coefficient of variation (ECV) pertaining to the test traits studied. Among agronomical characters, the GCV and PCV were reported to be in higher estimate for number of productive tillers per plant, number of grains per panicle, single plant yield and among quality characters for gelatinization temperature (GT), length breadth (LB) ratio, gel consistency and amylose content. The present study adverted that among the yield and grain quality characters viz., number of productive tillers, number of grains per panicle, single plant yield, plant height, 1000 grain weight, milling percentage and grain length could be easily inherited to next generation due to high heritability. Whereas breadth elongation ratio and linear elongation ratio are influenced by environmental factors due to their low heritability. Further, the number of productive tillers, number of grains per panicle, single plant yield, plant height, Gel consistency and amylose content exhibited higher PCV, GCV, heritability and genetic advance and hence direct selection can be made for target traits.

ESTIMATING VARIABILITY, HERITABILITY, AND GENETIC ADVANCE OF RICE GENOTYPES IN MID-HILLS OF NEPAL

<p>Rice is an essential staple food in Nepal but researches and varietal improvement programs are rarely carried out due to inadequate variability study. The field study was carried to diagnose the influence of genetic and environmental factors on yield traits to aid future rice breeding programs. Twelve genotypes were arranged in randomized complete block design with three replications from July to November 2019 at the research field of the Institute of Agriculture and Animal Science, Tribhuvan University, in the hilly area of Nepal. Analysis of variance showed significant difference for days to 50% booting, days to 50% flowering, plant height, panicle length, flag leaf area, filled grains per panicle, unfilled grains per panicle, fertility percentage, effective tillers m^-2, straw yield, grain yield, 1000-grain weight, and harvesting index indicating the presence of variation in genotypes. LPN BR-1615 was the most promising genotype in grain yield. The values of Phenotypic Coefficient of Variation (PCV) were higher than Genotypic Coefficient of Variation (GCV) for each trait and low difference between them was found for days to 50% booting, days to 50% flowering, plant height, panicle length, grain yield, thousand-grain weight, fertility percentage, and harvesting index. Plant height, effective tillers m^-2, and grain yield showed high heritability (i.e. 93.2%, 60.5% and 92.6%, respectively) and higher genetic advance as percentage of mean (i.e. 46.5, 34.6 and 50.1, respectively) . Thus, the experiment revealed that selections favoring plant height, effective tillers m^-2, and grain yield would help in effective breeding programs of rice in future.</p>

Estimation of Genetic Variability, Heritability and Genetic Advance in Potato (Solanum tuberosum L.) Genotypes for Tuber Yield and Yield Related Traits

Potato is a high potential food security crop in Ethiopia. Genetic variability is the basis of all crop improvement programs. The study was conducted at Adet in 2018 with the objective of assessing the extent and pattern of genetic variability of potato genotypes for yield and yield related traits. A total of 36 potato genotypes were evaluated for 18 quantitative traits in simple lattice design. The analysis of variance revealed that highly significant difference among the tested potato genotypes for all quantitative traits except stem number per hill. The phenotypic coefficient of variation was ranged from 4.56 to 56.01% (for specific gravity and unmarketable tuber yield ha-1 respectively) and the genotypic coefficient of variation was ranged from 2.32 to 40.66% (specific gravity and late blight severity percentage respectively). Days to attain 50% emergence, leaf area index, number of marketable and total tubers per plant, marketable and total tuber yield ha-1, and late blight severity percentage showed high heritability and high genetic advance as percent of mean. Most of the traits had high phenotypic coefficient of variation and genotypic coefficient of variation; and coupled high heritability with high genetic advance as percent of mean. Traits having high heritability and high genetic advance as percent of means is effective for simple selection.

Genetic Variability Studies for Yield and Yield Contributing Traits in Rabi sorghum (Sorghum bicolor L. Moench) in Relation to Drought Tolerance

Genetic variability studies were useful for effective selection in a crop species. Presence of desirable variation and the amount of that variation which is heritable is the primary requirement of any breeding program for the crop improvement. Therefore any breeding program for crop improvement depends majorly on the knowledge pertaining to genetic variability, heritability and genetic advance. The genetic variability study was carried out for yield and yield contributing traits in thirty-seven genotypes of rabi sorghum with three checks namely M 35-1, Phule Suchitra and CSV-22-R at Sorghum Research Station, V.N.M.K.V., Parbhani during rabi 2019. A randomized block design was used with three replications and these treatments were evaluated and data pertaining to eleven traits were recorded with the objective to estimate the genetic variability for the quantitative traits. This investigation revealed presence of highly significant differences among the genotypes indicating presence of large amount of variability in all the eleven characters studied. The study indicated presence of higher estimates of phenotypic coefficient of variation (PCV) for all the traits when compared to genotypic coefficient of variation (GCV) and these estimates are of lower magnitude. Among the forty genotypes studied VJV 107, VJV 106, PEC 30, RSV 1921, RSV 1945 and RSV 1984 were considered as the superior genotypes as these recorded better performance. Higher estimates of GCV and PCV were recorded for the traits; days to 50 per cent flowering, plant height, panicle length, panicle width, fodder yield per plant, biological yield per plant, harvest index and grain yield per plant indicating selection for higher values of these traits of sorghum would be effective. Whereas high heritability coupled with moderate to high genetic advance was observed for traits like plant height, fodder yield per plant and total biomass per plant.

Estimates of Heritability and Genetic Advance for Yield Components of Cowpea (Vigna unguiculata L. Walp) under Drought Stress Conditions

The study was conducted at the Teaching and Research Farms, Federal University of Agriculture, Makurdi, Nigeria. Five Cowpea genotypes (FUAMPEA-1, IT99K-573-1-1, SAMPEA-16, SAMPEA-8, BIU LOCAL) were crossed and advanced to F1, F2, BC1 and BC2 populations using bi-parental mating design. The six generations were evaluated in a Randomized Complete Block Design with three replications. Significant test of the mean performances among the entries showed significant differences among the generations for the characters studied. Wide ranges of narrow sense heritability (18 to 79%), broad sense heritability (21 to 92%) and genetic advance (5.7 to 24.1%) were obtained for characters studied. Broad and narrow sense heritability as well as genetic advance was moderate to high for most of the characters studied such as days to 50% flowering, plant height, days to pod maturity, number of seeds per pod, number of pods per plant, hundred seed weight, root length and grain yield for the three sets of cowpea crosses. The results also revealed the possibility of exploitation for grain yield and drought tolerance in the crosses studied.