PRODUCTION OF POLYHAPLOIDS OF HEXAPLOID WHEAT USING STORED PEARL-MILLET POLLEN

The effects of drying and freezing on viability of pearl millet pollen were examined with the aim of using stored pollen in polyhaploid prod uction of hexaploid wheat. Freshly collected pollen of pearl millet li ne NEC 7006 with 55% water content, germinated at a frequency of 80%. Pollen that was dried for two hours to 6% water content showed 50% ger mination frequency and maintained similar frequencies after the freezi ng process. In crosses of hexaploid wheat variety Norin 61 with fresh pearl millet pollen, embryos were obtained at a frequency of 27.6%. In crosses with pollen stored at -196 degrees C, -80 degrees C and -20 d egrees C for one month, embryo formation frequencies ranged from 27.5 to 17.4%. After five and twelve months of storage, the frequencies ran ged from 29.7 to 14.6% at storage temperatures of -196 degrees C and - 80 degrees C, and from 8.0 to 3.2% at -20 degrees C, indicating signif icant differences among storage temperatures. However, no significant frequency difference was found among pollen water contents at the time of collection. All plants regenerated from crosses with pearl millet pollen stored for five months were wheat polyhaploids. These results s uggest that stored pearl millet pollen is an efficient medium for prod ucing polyhaploids in hexaploid wheat.