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.

Genome wide association mapping for identification of QTL(S) underlying resistance to Alternaria blight (Alternaria brassicae (Berk) Sacc.) in Indian mustard (Brassica juncea L. Czern. & Coss.)”

Disease screening against Alternaria blight under field condition showed that, none was free from disease only 13 genotypes were found MR and 152 genotypes were found MS, 252 S and 3HS. The high estimate of phenotypic and genotypic coefficient of variation was recorded for YPP and SB., high estimate of broad sense heritability was recorded all characters except YPP. The genetics advance in per cent of mean was found high for PB, high heritability along with high genetic advance was observed for HPF. At phenotypic and genotypic level both YPP shoes highly significant and positive correlation. At phenotypic and genotypic level path coefficient reveled that in HPF, PL. The genotypes were grouped into eight different non overlapping cluster (five 115, three 100, six 84, one 78, seven 37 and three, two and four 1, eight 36 genotypes). The maximum and minimum inter cluster distance was between six, eight and one, three. One highest cluster mean for PH, MAT, and HPF and two (MAT, PH, HPF). Three (MAT, PH, HPF) four (MAT, PH, HPF) five (PH, MAT, HPF) six (MAT, PH, HPF) seven (MAT, HPF. PH), eight had no values due to reason no geminated or un survived plant and GWAS analysis of identified six significant association for Alternaria blight resistance on chromosome (A07, A09, A03, B07, B04, B03) respectively, This study showed that the diversity panel of Indian mustard identified QTLs for controlling of disease resistance against Alternaria blight in Indian mustard.

Genetic variability of some agronomic traits in a collection of wheat (Triticum turgidum L. ssp) genotypes under South Mediterranean growth conditions

Genetic variability of some agronomic traits were investigated in 60 tetraploid wheat accessions (Triticum turgidum L. ssp) under rainfed conditions. The results indicated the presence of sufficient variability for all measured traits.The highest phenotypic and genotypic coefficient of variation was recorded for yield and awn length. High heritability coupled with high genetic advance and high expected response to selection recorded for thousand-grain weight, awn length, and the number of grains per spike. Cluster analysis grouped the 60 wheat genotypes into five clusters. Clusters are relatively formed according to the geographical origin of the genotypes. Cluster III carried entries having the best combinations for all the traits; in which genotypes PI 127106, PI 192658, PI 29051 and PI67343 can represent an important reservoir of useful genes for the development of new wheat cultivars. Thousand-grain weight, biomass, awn length and harvest index could be used as a selection criterion for hybridization programs in the future. Highlights - The genetic variability of 9 traits of 60 wheat varieties was investigated. - There was great variability among wheat genotype for all measured traits. - There were wheat varieties shows highest phenotypic and genotypic coefficient of variation. - Some wheat genotypes may be desired allele reservoirs. - Some traits can be an alternative in wheat selection.

Study of Genetic Variability and Heritability in Cherry Tomato (Solanum lycopersicum L. Var. cerasiforme) Genotypes

Twenty-nine genotypes of cherry tomato (Solanum lycopersicum L. var. cerasiforme) were evaluated for their genetic variability and heritability. A wide range of genetic variability was observed for twenty traits of cherry tomato genotypes. The analysis of variance was significant for all the characters indicating genetic variability in the genotypes under the study except number of locules per fruit. The highest phenotypic and genotypic coefficient of variation were observed for lycopene (43.12, 42.94), total carotenoids (42.82, 42.51), average fruit weight (42.52, 42.50), fruit yield per hectare (42.29, 42.24). In general Phenotypic Coefficient of Variation (PCV) was marginally higher than the corresponding Genotypic Coefficient of Variation (GCV) indicating the less influence of environment in the expression of traits under study. High heritability coupled with high genetic advance as percentage of mean was observed for almost all characters indicating that most of the traits studied were mainly controlled by additive gene effect and thus selection may be effective.

Variability and Association Studies for Yield and Yield Related Traits in Pigeonpea [Cajanus cajan (L.) Millsp.]

Background: Study of phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) reveals the extent of phenotypic and genotypic variability in given population, respectively. Correlation and path analysis helps in identifying suitable selection criteria for improving the crop yield.Methods: Plant material comprised of 68 genotypes belongs to early maturity group of pigeonpea and experiment conducted during Kharif 2015-16 in randomized complete block design with two replications. Result: Traits, seed yield per plant (GCV=51.56%, h2=97.13%, GAM=104.67%) and number of pods per plant (GCV= 49.01%, h2=99.07%, GAM=100.49%) had high values of genotypic coefficient of variation (GCV), heritability (h2) and genetic advance as % of the mean (GAM) which indicated their additive genetic control. Plant height and number of seeds per pod recorded moderate to low heritability coupled with low GAM, indicating non-additive genetic control for these characters. Correlation analysis has revealed significant and positive association of seed yield per plant with number of pods per plant, plant height, secondary branches per plant, 100-seed weight and primary branches per plant. Path coefficient analysis identified number of pods per plant, secondary branches per plant and 100-seed weight as major traits affecting seed yield per plant directly and indirectly. The number of pods per plant and 100-seed weight should be given greater emphasis for improvement of seed yield in pigeonpea.

Genetic worth of multiple sets of cowpea breeding lines destined for advanced yield testing

The objective of this study was to determine genetic potentials in eight sets of cowpea lines for grain yield (GY), hundred seed weight (HSDWT) and days to 50% flowering (DT50FL). A total of 614 F6 genotypes constituting the sets, grouped by maturity, were evaluated across two locations in Northern Nigeria, in an alpha lattice design, two replications each. Data were recorded on GY, HSDWT and DT50FL.Variance components, genotypic coefficient of variation (GCV), and genetic advance (GA) were used to decode the magnitude of genetic variance within and among sets. Genetic usefulness (Up) which depends on mean and variance to score the genetic merits in historically bi-parental populations was applied to groups of breeding lines with mixed parentage. Principal component analysis (PCA) was used to depict contribution of traits to observed variations. GY and DT50FL explained the variance within and between sets respectively. Genotypes were significantly different, although genotype-by-location and set-by-location interaction effects were also prominent. Genetic variance (δ2G) and GCV were high for GY in Prelim2 (δ2G = 45,897; GCV = 19.58%), HSDWT in Prelim11 (δ2G = 7.137; GCV = 17.07%) and DT50F in Prelim5 (δ2G = 4.54; GCV = 4.4%). Heritability varied among sets for GY (H = 0.21 to 0.57), HSDWT (H = 0.76 to 0.93) and DT50FL (H = 0.20 to 0.81). GA and percentage GA (GAPM) were high for GY in Prelim2 (GAPM = 24.59%; GA = 269.05Kg/ha), HSDWT in Prelim11 (GAPM = 28.54%; GA = 4.47 g), and DT50F in Prelim10 (GAPM = 6.49%; GA = 3.01 days). These sets also registered high values of genetic usefulness, suggesting potential application in non-full sib populations. These approaches can be used during preliminary performance tests to reinforce decisions in extracting promising lines and choose among defined groups of lines.

An anatomical screening of white jute accessions for fibre content

The present study was conducted to evaluate the performance of 24 advanced lines of white jute and four check varieties ( CVL-1, CC-45, BJRI Deshi Pat-7 & BJRI Deshi Pat-8) for screening out high yielding and better quality fibre through an anatomical approach at JAES, Manikganj. The experiment was conducted in randomly complete block design (RCBD) with three replications. The cultivars revealed significant differences among them for all the characters with range of variability. The highest bark thickness (2.32 mm) was noticed by the accession C-5036 which performed significantly better than the two checks and lowest was recorded by C-5126 (1.07 mm). The variety BJRI Deshi Pat-8 observed significantly the highest number of pyramid (54.13) whereas the lowest was recorded by the varieties BJRI Deshi Pat-7 (28.23). The accession C-5117 showed significantly the highest number of layer (10.29) whereas the variety, BJRI Deshi Pat-7 showed significantly lowest number of layer (6.32). The accession C-2305(92.37) and C-12221 (91.19) significantly showed top two number of fibre bundle, however, the lowest number of fibre bundle was recorded by BJC-5105(42.79). The largest area of pyramid was observed by the accession C-5036 (46.85 sq. mm) whereas the lowest was showed by BJC-5105 (14.50 sq. mm). The differences between Phenotypic Coefficient of Variation (PCV) and Genotypic Coefficient of Variation (GCV) were little for all the characters indicating these characters were less influenced by the environment. Heritability and genetic advance (GA) were high for number of pyramid, number of fibre, bundle and Area of pyramid (sq.mm). Three accessions(C-12221, C-2305, C-5036) are showed the best performance than other accession on our screening program. These accessions are included in cluster V among the five clusters which exhibit the highest performance in all parameter except number of pyramid and may be used in further hybridization of jute.

Hybrid vigour and variability for key growth characters and yield in cashew (Anacardium occidentale L.)

Hybrid vigour and assessment of genetic variability for important growth characters and yield traits in cashew were studied in eight cashew hybrids.The analysis of variance for the phenotypic data for 12 characters revealed significant variation among the genotypes except for tree spread, flowering laterals per m2, non-flowering laterals per m2 and sex ratio.The highest nut weight was observed in H-125 (12.07 g) whereas the lowest was in H-2452 (5.08 g).The maximum nut yield was noticed in hybrid H-126 with 5.96 kg tree-1 while NRCC Selection-2 recorded lowest with 0.53 kg tree-1. The standard heterosis over two checks, bold nut check (NRCC Sel-2) and high yielding check (Bhaskara) and variability parameters such as genotypic coefficient of variation, phenotypic coefficient of variation, broad-sense heritability and genetic advance were estimated. For nut weight, standard heterosis over bold nut check varied from -34.54 to 55.54 per cent and six out of eight hybrids viz., H-43, H-66, H-68, H-125, H-126 and H-2473 showed significant and positive standard heterosis. Standard heterosis over the high yielding check, varied from -38.93 to 300 per cent and it was significant and positive in two hybrids viz., H-126 and H-125 with 300 per cent and 214.09 per cent, respectively.The hybrid vigour was not significant for trunk girth, tree height, tree spread, number of flowering laterals per m2 and sex ratio. Notably, five hybrids presented more than 20 per cent standard heterosis for nut weight over bold nut check which may serve as a useful source of breeding material. Two hybrids viz., H-125 and H-126 showed good hybrid vigour for nut weight and yield over two checks and thus have been inducted into multi-location trials and also under consideration for release.

An Estimate of Variability, Heritability and Genetic Advance for Grain Yield and Yield Components in Bread Wheat (Triticum aestivum L.)

Problem: Wheat (Triticum aestivum L.) is one of the principal cereal crops grown worldwide and one of the important staples of nearly 2.5 billion of world population. India ranks second position in terms of both in area and production after china. The substantial improvement in production is utmost necessary to feed the growing population. Objective: In India, wheat requirement by 2030 has been estimated at 100 million metric tons and to achieve this target, wheat production can be increased either through horizontal approach i.e. by the increasing area under cultivation or through vertical approach i.e. varietal/ hybrid improvement. For effective selection and utilization of superior genotype in the germplasm lines, knowledge of genetic parameters such as genetic variability, heritability and genetic advance is essential. Materials and Methods: The experimental material comprised of ten parents, their 45 F1s and 45 F2s developed by the crossing of 10 parents viz. HUW 510, HUW 234, HUW 468, UP 2338, HD 2402, RAJ 1972, HD 2329, LOK-1, SONALIKA and K 65 in half-diallel programme to study the fourteen characters. The final trial of F1, F2 including parents was conducted during Rabi 2014-15 with three replications employing Randomized Complete Block Design at Research Farm, BRDPG College, Deoria, Uttar Pradesh, India. Result: Wider range of phenotypic coefficient of variation (PCV) was observed for all the traits in F1 generation ranged from 2.19 (days to 50% flowering) to 13.47 (leaf area index) while, genotypic coefficient of variation (GCV) ranged from 1.50 (days to 50% flowering) to 11.28 (leaf area index). High heritability was observed in both F1 and F2 generation for leaf area index and day to maturity while, moderate to low level of heritability was recorded for other characters. The high value of genetic advance was not recorded in both F1 and F2 generation. Only moderate to the low value of genetic advance was observed for all the fourteen characters under study. Conclusion: Estimate of phenotypic and genotypic coefficient of variation of fourteen characters in both generations reveals sufficient variability indicating ample scope for genetic improvement of these traits through selection. Moderate level of heritability accompanied with a moderate level of genetic advance was observed for plant height, leaf area index, days to maturity and grain yield per plant in both F1 and F2 generation indicates additive gene effect and selection may be effective.

Genetic variability, heritability, genetic advance and correlation among yield and yield components of rice (Oryza sativa L.)

This study was conducted during summer 2015 at Regional Agriculture Research Station, Dipayal, Doti, Nepal to estimate the genotypic and phenotypic variability, heritability, genetic advance and correlation on grain yield and yield associated traits using 26 advance genotypes of lowland irrigated rice. Analysis of variance revealed the existence of significant difference for days to flowering, maturity, plant height, panicle length, thousand grain weight and grain yield. High heritability was estimated for days to flowering (0.88), maturity (0.79), thousand grain weight (0.48) and plant height (0.43) suggesting these traits are under high genetic control. High phenotypic variation was observed for grain yield (24.87%), number of grains/panicle (22.45%), number of panicles/m2 (20.95%) and straw yield (20.75%) while grain yield had medium (12.02%) and remaining traits showed low genotypic coefficient of variation (<10%). High phenotypic coefficient of variation estimated as compared to genotypic coefficient of variation showed environmental influence on the expression of traits. Grain yield (11.98) and days to flowering (10.32) showed medium and remaining traits sowed low genotypic advance as percent of mean. High to low heritability with moderate to low genotypic advance as percent of mean suggested these traits were governed by non additive gene thus direct selection is not beneficial. Further improvements on yield potentiality and yield traits on these genotypes are suggested by creating variation and selection. Panicle length (r = 0.230), days to flowering (r = 0.247), effective tillers (r = 0.488) and straw yield (r = 0.846) manifested significant positive association with grain yield indicating that yield can be increased if selection applied in favor of those yield components.