Genetic variability in late kharif (Rangada) onion (Allium cepa L.)

Abstract: An investigation was carried out to study the genetic variability in late kharif germplasm of onion at Nashik, Maharashtra (India). The mean data indicated that the highest gross yield (41.17 t/ha) and marketable yield (39.13 t/ha) was recorded in line 744 and was at par with line 682 (39.07 t/ha) and (34.39 t/ha). A wide range of variability was observed for gross yield (19.65 to 41.17 t/ha), marketable yield (10.05 to 39.13 t/ha), bulb size index (20.40 to 35.90 cm²), bolters (0.00 to 40.83%), doubles (0.00 to 47.50 %), thrips/plant (8.75 to 25.80) and plant height (54.95 to 71.80 cm). A higher magnitude of coefficient of variation was recorded for bolters (112.78 -112.65%), followed by doubles (86.35-86.16%), thrips/plant (37.55-37.36) and marketable yield (29.34 and 29.90 %). Highest heritability was noted in doubles, gross yield, bulb diameter, plant height, bolters and thrips/plant. The genetic advance as percent of mean ranged from 3.93 to 231.73. High genetic advance noted in bolters (231.73 %), doubles (177.12 %), thrips/plant (76.56%) and marketable yield (54.53%) and rest of others characters showed medium to low genetic advance. Gross yield, marketable yield, doubles, bolters, thrips/plant and bulb size index indicated higher estimates of genetic advance as percent of mean coupled with high heritability, suggesting the involvement of additive genetic variance for these traits. Marketable yield was significantly and positively correlated with plant height, neck thickness, bulb diameter, bulb size index, weight of 20 bulbs, and gross yield and negatively correlated with bolters, doubles and days for bulb initiation at genotypic and phenotypic levels. Plant height, leaves/plant, bulb diameter, bulb size index, weight of 20 bulbs and days for bulbs initiation. The study revealed that a wide range of variability for important characters exists in germplasm offering a good scope for developing improved onion varieties suitable for cultivation in Maharashtra.