Physio-norphological Studies For F1 Hybrid Rice (Oryza sativa L) Using Japonica-Indica Cross

本研究以温敏核不育系T29为母本，以籼、粳为父本配制杂交水稻，研究其光合和农艺性状的杂种优势，为水稻的栽培提供理论依据。温敏核不育系T29在抽穗前15-11天的日平均温度为24.1℃以上时不育。在冲绳，6月16日至11月抽穗时，由于温度超过24.1℃，花粉和小穗完全不育。在20-35℃温度范围内，T29杂种F_1的光合能力（以CO_2交换率表示）低于父本。相反，在40℃下，随着蒸腾速率的增加，气孔导度也随之增加，这是导致杂种优势大于父本和父本的原因。 ...更多信息 在F_1代中，CER表现为中亲。以5个温敏核不育系与籼、粳型品种杂交的F_1代为材料，研究了其在分蘖活跃期、开花期和面熟期某些生理形态性状的杂种优势。绝大多数F_1代的CER在各生育期均低于各自的父本，主要原因是叶片含氮量较低。在生育期内，由于分蘖数和单株叶面积均较大，各杂种F_1的干物质生产均表现出高于父本和中亲的正优势。大多数F_1杂种在籽粒产量和每穗颖花数方面均表现出相对于父本的正杂种优势。幼穗分化期的干物质生产量是杂种F_1产量优势的主要来源。本研究为温敏核不育系T29与多个籼、粳稻品种杂交F_1的杂种优势及栽培提供了有效的信息。少

This study was carried out to investigate the heterosis for photosynthetic and agronomic charactes, and provide information regarding to cultivation in F_1 hybrid rice produced by crossing a thermo-sensitive genic male sterile (TGMS) T29 line with several indica and japonica cultivers. The (TGMS) T29 line was sterile when exposed to daily mean temperatures of 24.1℃ or above during the stage from 15-11 days before heading. It was completry sterile for both pollen and spikelet when the plant headed from June 16 to November in Okinawa, because the temperature exceeded 24.1℃. The fact indicates that it can be used for F_1 hybrid seed production during this period in Okinawa.Within a temperature range of 20-35℃, photosynthetic ability in term of CO_2 exchange rate (CER) in the F_1 hybrid from the T29 line was lower than the male parent. On the contrary at 40℃, a higher stomatal conductance according to higher transpiration rate was cause of positive heterosis value over both male parent and … More mid-parent for CER in the F_1 hybrid. The higher CER in the F_1 hybrid might be also due to a higher non-photochemical quenching.Heterosis for some physio-morphological characters were investigated in five F_1 hybrids between the TGMS line with indica and japonica cultivars at the active tilllering, flowereing and dough-ripe stages. CER was lower in most F_1 hybrids than in their respective male parent at all stages, mainly due to the lower leaf nitrogen content. During the growing season, a positive heterosis value over the male parent and mid-parent for dry matter production was observed in all F_1 hybrids due to both the larger number of tiller and the larger leaf area per plant. Most F_1 hybrids showed positive heterosis value over the male parent for grain yield and the number of spikelets per panicle. The higher dry matter production at the panicle initiation stage contributed to the heterosis for grain yield in F_1 hybrids. The heterosis for grain yield in the F_1 hybrids also due to the larger number of panicles per plant and especially the larger number of spikelets per panicle.Thus, the effective information regarding to heterosis and cultivation in F_1 hybrid rice produced by crossing a thermo-sensitive genic male sterile (TGMS) T29 line with several indica and japonica cultivers was attained in this studies. Less