Combining ability for quantitative traits in bread wheat (Triticum aestivum L.)

Abstract

The present investigation was carried out to estimate the combining ability and type of gene action governing the inheritance of important traits including rust resistance in bread wheat (Triticum aestivum L.). Twelve bread wheat genotypes comprising of six lines (Agra local, Lal Bahadur, NI-5439, C-306, Sonalika and Pusa-4) and six testers (I:1D-2189, NIAW-34, GW-324, DWR-248, DWR-247 and PBW-343) were crossed in a L x T mating design during rabi 2001-02. The 36 crosses produced and their parents were raised in randomized complete block design with two replications at Ugar Khurd under irrigated conditions. In each replication, single row of parents and F1s were sown in 2 m row length with spacing of 5 cm between plants and 25 cm between rows. The data were recorded on five randomly chosen plants for twelve quantitative traits viz., days to 50 per cent flowering, days to maturity, plant height (cm), number of tillers per plant, number of spikes per m2, peduncle length (cm), spike length (cm), number of grains per spike, total biomass per plant, grain yield per plant, harvest index and 1000-grain weight (g). Leaf rust disease severity score was visually recorded three times at 15 days interval from tillering throughout green leaf stage. The data were later transformed into average coefficient of infection (AC1) by multiplying the per cent infection with response value assigned to each infection type as per Loegering rate [2]. The statistical analysis for combining ability was done as per the procedure developed by Kempthorne [3].