Department of Plant Breeding, Punjab Agricultural University, Ludhiana
*Present address: Wheat Breeding Station, Bhowali, Dt. Naini Tal (U.P.)
The effects of the presence or absence of awns were studied in pairs of awned vs. awnleted populations tracing back in their pedigree to individual F2 plants heterozygous for the locus controlling this character. Presence of awns on the spike was found to increase 1000-grain weight and yield per plot but delayed maturity slightly. Favourable effects of the awns were also detected on tiller number, grain number per spike and grain number per spikelet. These effects were unfavourable in the case of ear length and spikelet number. All the associations were found to be breakable which was attributed to (i) recombination in the chromosomal segments, near the locus governing awns, (ii) interaction of the effects of a-locus with background genotypes. The influence of awns on yield and 1000-grain weight seemed to be partly due to physiological causes as the awns provide an additional photosynthetic area in the ear. The probable cause of accumulation of desirable genes for several characters near the a-locus have been discussed.
