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

Abstract

Development of suitable varieties of onion with high yieldas well as good shelf life through crossing between longand short-day onion was carried out at the Research Farmof ICAR-Directorate of Onion and Garlic Research,Rajgurunagar, Pune in collaboration with ICAR-CITH,Srinagar. A total of 135 crosses were made between available15 exotic onion varieties and 9 short day lines at ICARCITH,Srinagar. The crosses were evaluated in their F2generation and further selection were continued up to F5generation. The experiment was laid out in randomized blockdesign with three replications during rabi seasons toinvestigate the genetic variability and response to selectionamong all the crosses. Top seven progenies which wereselected on the basis of high yield in F2 generation whichwere also good performers in F3 generation with high yieldand other desirable traits. The selected crosses were foundfree from doubles and bolters in F3 generation. This indicatesthe selection done from F2 to F3 generation is effective fordouble and bolter bulbs which certainly helps to increasethe marketable bulb yield. High degree of variation wasobserved for all the traits studied and the difference betweenphenotypic and genotypic coefficient of variation was foundto be narrow for most of the traits. More than 30% marketableyield enhancement was observed in four progenies viz.,Couger × DOGR-595, Reforma × DOGR-595, Mercedes ×Bhima Super and Collina × DOGR-597 in comparison withbest check Bhima Shakti (41.17 t/ha) in F3 generationwhereas, more than 50 t/ha marketable yield was recorded infour progenies viz., Basic × RGO-53, Couger × DOGR-595,Mercedes × Bhima Super and Reforma × DOGR-595 in F3generation.