Studies on one-step procedure in rice(oryza sativa) anther culture Ⅱ. Effects of 2,4-D, kinetin and ABA on direct plant generation

One-step culture in which the pollen plantlets are produced directly from either embryoids or embryogenic callus from microspores in a single operation of the culture procedure would save labors, time, laboratory materials and spaces required with two-step culture in which callus are induced in a medium and subsequently transferred to the different medium for plant development. Three phytohormones, 2,4-D, kinetin and ABA were added with combined formulations in N6 basal medium to determine the effects on the development of pollen plant through one-step procedure of anther culture without transferring callus. Two japonica(Cheonmabyeo and Chucheongbyeo) and two Tongil-type(indica/japonica) varieties(Milyang 23 and Taebaegbyeo) were used as donor plant materials. All the varieties used produced pollen plants in any one formulation of 24 treatment combinations from 4 weeks after anther plating with the large between- and within-varietal variability:0.6~26.3% for Cheonmabyeo, 0.3~13.5 % for Chucheongbyeo, 0~2.3 % for Milyang 23 and 01.5% for Taebaegbyeo. In general, the N₆ basic medium supplemented with 0.002-0.02mg/ℓ of 2,4-D showed higher plant regenerations for japonica varieties in one-step culture. The combination of 0.002mg/ℓ 2,4-D and 0.5mg/ℓ kinetin enhanced the frequency of direct plant production, while the effect of abscisic acid was not clear.