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.