Response to selection through introgression breeding in onion (Allium cepa L.)

Abstract

Development of suitable varieties of onion with high yield as well as good shelf life through crossing between long and short-day onion was carried out at the Research Farm of ICAR-Directorate of Onion and Garlic Research, Rajgurunagar, Pune in collaboration with ICAR-CITH, Srinagar. A total of 135 crosses were made between available 15 exotic onion varieties and 9 short day lines at ICARCITH, Srinagar. The crosses were evaluated in their F2 generation and further selection were continued up to F5 generation. The experiment was laid out in randomized block design with three replications during rabi seasons to investigate the genetic variability and response to selection among all the crosses. Top seven progenies which were selected on the basis of high yield in F2 generation which were also good performers in F3 generation with high yield and other desirable traits. The selected crosses were found free from doubles and bolters in F3 generation. This indicates the selection done from F2 to F3 generation is effective for double and bolter bulbs which certainly helps to increase the marketable bulb yield. High degree of variation was observed for all the traits studied and the difference between phenotypic and genotypic coefficient of variation was found to be narrow for most of the traits. More than 30% marketable yield enhancement was observed in four progenies viz., Couger × DOGR-595, Reforma × DOGR-595, Mercedes × Bhima Super and Collina × DOGR-597 in comparison with best check Bhima Shakti (41.17 t/ha) in F3 generation whereas, more than 50 t/ha marketable yield was recorded in four progenies viz., Basic × RGO-53, Couger × DOGR-595, Mercedes × Bhima Super and Reforma × DOGR-595 in F3 generation.