Mutant conferring partial male sterility: a versatile system for unrestrained hybridization in a highly autogamous finger millet crop.

MAIN

conclusionPartial male sterile mutant offers high hybrid recovery and seed set upon crossing. Partial sterility is recessive, monogenic and caused due to impairment of pollen function, which is supported by ddRAD sequencing. Finger millet, a nutri-cereal, has wider adaptability mainly grown as a rainfed crop in arid and semiarid tropics of Asia and Africa. Highly autogamous nature and small florets makes the hybridization tedious and hence the genetic improvement has been very slow. To address this, a novel partial male sterile mutant (ps1) was characterized extensively in line of its utility in hybridization breeding. An in vivo pollen study using fluorescence microscopy revealed the cause of partial male sterility in ps1 mutant as impairment of pollen germination and pollen tube growth on stigma. The mutant sets ~ 10% seeds upon bagging, 20% under open pollination and up to 49% in controlled crossing. Hybrid recovery (outcrossing) in 46 crosses with ps1 ranged from 28.6% to 81.2% with an average of 56.7% under controlled crossing. An extensive genetic study using 46 F