Indian Society of Genetics & Plant Breeding

Selection indices for enhanced selection efficiency in Indian mustard under terminal heat stress conditions

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With global increase in temperature, terminal heat stress

(THS) has emerged as a major challenge in food crops.

Indian mustard (Brassica juncea L. Czern & Coss), C3 plant,

grows well at 15-20°C. Heat stress at seedling as well as at

flowering stage leads to enhanced vegetative growth and

flower abortion leading to loss in seed yield. Late sowing

after cotton and rice harvest expose the crop to high

temperature stress during reproductive stage of

development. A fixed diversity stock of 486 Indian mustard

lines were evaluated under delayed planting conditions to

expose the crop to THS for two consecutive years. Selection

indices were computed using four different combinations

of traits via Kang_SAS Path computer program along with

expected genetic advance (GA) at 5% selection intensity.

Set1, comprised of five traits viz., plant height (PH), number

of secondary branches (NSB), number of siliquae on main

shoot (NSMS), seed yield (SY) and 1000-seed weight (TSW)

were recorded the highest GA (8.612) in comparison to

other trait combinations tested in present study. Other

important finding was slight difference in GA of set I (8.612;

SY included) and set II (8.599; SY excluded) with efficiency

of selection index 131% and 130%, respectively. This

recommended that in initial breeding generations (F2/F3), a

breeder may base his selection on four yield related traits

(PH, NSB, NSMS and TSW) only without significant loss in

genetic gains. This will save resources and time of breeders

to compute seed yield. This is the first report on computation

of selection index for efficient simultaneous selection under

THS in Indian mustard.

Keywords: Brassica juncea, terminal heat stress, direct effects, indirect effects, yield traits


Year: 2020
Volume: 80
Issue: 1
Article DOI: 10.31742/IJGPB.80.1.13
Print ISSN: 0019-5200
Online ISSN: 0975-6906



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