Breeding of Aromatic Rice (Oryza sativa L.) Variety KDML 105 for Photoperiod Insensitivity through Anther Culture of F1 Hybrids

Abstract

Breeding of aromatic rice (Oryza sativa L.) variety KDML 105 for photoperiod insensitivity was conducted using anther culture of F1 hybrids. Two F1 hybrids were made by crossing between aromatic rice varirty KDML 105 which was photoperiod sensitive and the other two aromatic rice varieties, IR 841-85-1-2 and Basmati 370 which were photoperiod insensitive. Panicles of both hybrids were collected when the distance of the flag leaf auricle to that of the next leaf was between 5-12 cm. Anthers containing microspores at the mid-late uninucleate stage were cultured on modified N6 medium supplemented with 1, 2, 3 and 4 gm/l 2,4-D and 3 and 5% sucrose for callus induction. It was found that modified N6 medium supplemented with 2 mg/l 2,4-D and 5% sucrose gave the highest frequency of callus induction, 6.2 and 5.8% for the hybrids of KDML 105/IR 841-85-1-2 and KDML 105/Basmati 370, respectively. Calli of the hybrid of KDML 105/IR 841-85-1-2 when transferred to MS medium supplemented with 1 mg/l NAA, 4 mg/l kinetin and 2% sucrose could regenerate into green shoots at the frequency of 6.2%. While calli of the hybrid of KDML 105/Basmati 370 gave 1.0% green shoot regeneration on the same medium. Shoots were rooted when transferred onto MS medium without growth regulator. Among the 60 anther-derived plants (H1) of the hybrid of KDML 105/IR 841-85-1-2 produced, 38 haploid plants (63.3%) and 22 doubled haploid plants (36.7%) were recovered. The H1 plants showed high variation in morphology and agronomic characters. However, all of the H1 plants were photoperiod sensitive similar to female parent KDML 105. The desirable photoperiod insensitive plants was not recovered due to the small number of H1 plants.