การพัฒนาและการสุกแก่ของเมล็ดพันธุ์และตำแหน่งรวงต่อคุณภาพเมล็ดพันธ์ข้าวไร่พันธุ์ลืมผัว

Abstract

Seed development and maturation and panicle position on seed quality of upland rice cv. Leum Pua were studied at the Department of Plant Science, Faculty of Natural Resources, Prince of Songkla University, Hat Yai campus, Hat Yai, Songkhla, from July to December, 2015. The upland rice seed was planted in a field and the panicles were tagged at the first date of the flower started blooming to indicate the date of flowering. The panicles at 9, 12, 15, 18, 21, 24, 27, 30, 33, and 36 days after flowering were harvested to investigate seed color and seed quality. The results showed that the upland rice seed cv. Leum Pua had five stages of color development: green, green with red-purple line, yellow with brown-purple line, yellow with black line and yellow, respectively. The upland rice seed cv. Leum Pua reached the physiological maturity at 30 days after flowering while approximately 85 % of seed in panicle turned yellow with maximum seed dry weight of 36.53 mg/seed and moisture content of 24.82 %. Seeds were dried at 40 °C for 48 hours had maximum seed quality with highest standard germination and soil emergence of 99.00 and 98.50 % respectively and the highest seed vigor in terms of mean germination time, seedling growth, seedling dry weight, germination after accelerated aging and low electrical conductivity. The panicles at physiological maturity stage were divided into three positions: top, middle and bottom and this seed were separately tested. The results showed that seed from the top and middle positions had higher quality than bottom position seed. However, seed from all positions had high germination and soil emergence of 95.00-99.00 and 89.50-97.50 % respectively and high seed vigor in terms of mean germination time, seedling growth, seedling dry weight and low electrical conductivity. For maximum quality seed production of upland rice cv. Leum Pua should be harvested at seed physiological maturity stage when approximately 85 % of seed in panicle turn yellow color.