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

Agronomic performance and genotypic diversity for morphological traits among early maize genotypes

Detailed information on the genetic diversity between maize germplasm (Zea mays L.) is useful for their systematic and efficient use in breeding programs. Fourteen early maize genotypes were studied to assess their performance and genotypic diversity at Doti, Nepal in 2015. Days to tasseling, days to silking, plant height, ear height, ear length, ear diameter and grain yield were significant among genotypes. Genotype SO3TEY-PO-BM, COMPOL-NIOBP and ACROSS-99402 were found higher yielder with earlier maturity. Days to tasseling (0.85), days to silking (0.82), plant height (0.79), ear length (0.71) and ear diameter (0.66) were found highly heritable traits. Grain yield (0.39) and ear height (0.47) medium and remaining traits showed low heritability. High PCV was observed for grain yield (35.10%), number of plants/plot (34.46%), tesseling silking interval (26.85%), harvested ears/plot (24.45%) and husk cover rating (22.85%) where other traits showed medium to low PCV. Grain yield showed high GCV (21.96%), ear height and husk cover had medium and remaining traits showed low GCV (<10%). Plant height (r₌0.498), harvested plants/plot (r₌0.412), harvested ear/plot (r₌0.762), ear length (r₌0.472) and ear diameter (r₌0.470) showed significant positive correlation with grain yield. The yield can be improved if selection applied in favor of those yield components

Agronomic performance and genotypic diversity for morphological traits among early maize genotypes

Detailed information on the genetic diversity between maize germplasm (Zea mays L.) is useful for their systematic and efficient use in breeding programs. Fourteen early maize genotypes were studied to assess their performance and genotypic diversity at Doti, Nepal in 2015. Days to tasseling, days to silking, plant height, ear height, ear length, ear diameter and grain yield were significant among genotypes. Genotype SO3TEY-PO-BM, COMPOL-NIOBP and ACROSS-99402 were found higher yielder with earlier maturity. Days to tasseling (0.85), days to silking (0.82), plant height (0.79), ear length (0.71) and ear diameter (0.66) were found highly heritable traits. Grain yield (0.39) and ear height (0.47) medium and remaining traits showed low heritability. High PCV was observed for grain yield (35.10%), number of plants/plot (34.46%), tesseling silking interval (26.85%), harvested ears/plot (24.45%) and husk cover rating (22.85%) where other traits showed medium to low PCV. Grain yield showed high GCV (21.96%), ear height and husk cover had medium and remaining traits showed low GCV (<10%). Plant height (r₌0.498), harvested plants/plot (r₌0.412), harvested ear/plot (r₌0.762), ear length (r₌0.472) and ear diameter (r₌0.470) showed significant positive correlation with grain yield. The yield can be improved if selection applied in favor of those yield components