Identification and development of male sterile and their maintainer lines in short-day onion (Allium cepa L.) genotypes

The performance of different onion genotypes was assessed for bolting traits because of identification and isolation of male sterile lines, significant results were revealed for number of bolts per plant, bolt length, umbel height, umbel diameter, number of flowers per umbel and number of flowers per plant. The male-sterile plants were spotted among the genotypes, which was phenotypically male sterile, in which flowers had the longer style with the narrow stigmatic knob, does produce functionally non-viable pollens, perianths of the male-sterile flower was not open fully. The anthers were light green to slightly yellowish translucent, shrivelled, seldom empty anther without pollen grains and were fused with anther sacs. The male-sterile plants were confirmed by acetocarmine assay and orf725 molecular marker. The identified male sterile lines will be used as parental material in future heterosis breeding to increase the onion bulb productivity.