Identification Of Marker Varieties On Drought Tolerance & Utilization Of Three-Way Hybrid From Paddy Rice And Upland Rice

This study consists of two parts.Part one:Basing on soil moisture gradient identification method(Liu et al.,2005),18 cultivated rice varieties were used to study drought performance in normal and drought treatments during flowering and grain filling stage.Drought related physiological and morphological traits were surveyed during the stress period.Agronomic characteristics,grain yield and yield components were evaluated after harvest.We investigated root characteristics of rice plants under normal and drought treatment via PVC tube approach.Part two:By the mating pattern of 'paddy rice CMS line/upland maintainer line//upland restorer line',we produced a three-way hybrid.We investigated the grain yield,yield components,drought tolerance and rice quality of the three-way hybrid in comparison with that of the related single cross hybrids.The main results were as follows:1.Before normal and drought treatment,the soil moisture content in the middle and side of screening island were 41.4%and 44%respectively.Using drainage and irrigation facility,24d after treatment,the moisture content in the middle and side of greenhouse were 7.9%and 42%respectively.The survey of plant trait in the middle and sides cultivated rice showed that the difference of plant height,effective panicle,leaf water potential,biomass,seed setting rate,canopy temperature and grain yield were at the significance or extremely significance level.These results showed that our drought identification methods could achieve normal and drought treatment at the same field, reducing environment error.2.The result of drought identification in greenhouse showed that plant height, effective panicle,leaf water potential,biomass,seed setting rate and grain yield all reduced;Canopy temperature increased.The result of drought identification in PVC tubes showed that root length,deep root weight,deep root volume,deep root weight rate,and deep root volume rate increase obviously.3.Basing on drought-resistance coefficient and comprehensive agronomic characters, we selected 5 "marker" varieties:IR55459-05(high resistance),MARAVILHA (resistance),MONOLAYA(medium resistance),IR30358-084-1-1(medium susceptible) and IR7790-18-1-2(susceptible).4.The field uniformity of paddy-upland three-way hybrid was slightly worse than that of related single cross hybrids,however,it could meet the need of production.The drought-resistance coefficient of three-way hybrid was 51.21%,higher than related single cross hybrid's 44.8%,25.88%.The rice quality of three-way hybrid was similar to related single cross hybrid.During the year 2007,the yields per plots of three way cross hybrid were 3.57%and 11.71%higher than related single cross hybrids.During the year 2006, the yields per plots of three way cross hybrid were 17.33%and 25.63%higher than related single cross hybrids.