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  • Author or Editor: W. N. Chang x
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Abstract

Male fertile lines M611B and P52-371B and male-sterile lines M2399A and P54-306A of onion were grown in 3 chambers in the Biotron with maximum temperatures of 24°C, 35°, and 43° and a minimum of 18°. Temperature and flower age affected longevity and viability of pollen. There was no striking difference in % germination between the 2 male-fertile lines in time of day pollen was collected from flowers of the same age. At 24° stigma receptivity was highest on the 4th day; at 35°, the 3rd day; and at 43°, the 1st day after anthesis. Pollen started germinating ½ hour after placement on the stigma at the 3 temperatures. Pollen tubes grew the entire length of the style within 12 hours after pollination. The highest % fruit set was at 35°. Seeds per ovary were 2.57, 3.20 and 1.66 for 24°, 35° and 43°, respectively.

Open Access

Abstract

Male-sterile onion lines, M2399A and P54-306A were hand pollinated with pollen from 2 male-fertile lines M611B and P52-371B, in 3 Biotron chambers with maxima temperatures of 24°, 35°, and 43°C, respectively, and a minimum temperature of 18°C. There was no significant effect of temperature on magagmetophyte development. Percent abortion of young seeds was 21, 11, and 66% at 24°, 35°, and 43°, respectively; 35° was more favorable for ovule, seed and ovary growth than 24° and 43°. The endosperm nuclei divided soon after fertilization and continued normally the first 5 days after pollination at all 3 temperatures. Subsequent growth of endosperm nuclei was retarded at 43° and only 1 or 2 seeds per ovary continued to grow at a normal rate. The first embryo division was observed 7 to 8, 5 to 6, and 6 to 7 days after pollination at 24°, 35°, and 43°, respectively.

Open Access