大穗型杂交水稻父本材料的抗旱性筛选与鉴定

培育大穗型品种是我国超级杂交稻主要育种目标之一，但大穗型水稻品种常存在结实率过低或结实不稳定等严重问题，而旱害常成为上述问题产生的直接原因。以21份大穗型水稻父本品种为供试材料，采用盆栽法，从花粉母细胞减数分裂期开始进行连续10 d的干旱处理（控制土壤相对含水量至40%~50%），研究了结实率和每穗总粒数的变化。结果表明，干旱处理后品种的结实率和每穗总粒数降低，敏感品种降低幅度显著大于强耐旱品种。试验共筛选出8个大穗型强耐旱父本材料，10个耐旱型父本材料，3个敏感型父本材料。其中R527和9 311选的结实率和总粒数在干旱条件下都表现良好。2个耐旱性差异品种的授粉生物特性分析发现，干旱处理后各品种的花药长度、每柱头花粉总数和萌发数及萌发率均降低，强耐旱型品种R527降低幅度较小；而敏感型品种BL006降低幅度较大，花药长度、每柱头花粉萌发数及萌发率对照和处理间存在极显著差异。研究表明，结实率和每穗总粒数可以作为大穗型品种耐旱性筛选与鉴定的联合指标，花药长度和每柱头花粉萌发率可作为重要的参考指标，大穗型水稻品种耐旱性差异与其在干旱条件下雄性配子的形成及其活力密切相关

SCREENING AND IDENTIFICATION OF DROUGHT RESISTANCE OF LARGE-PANICLE MALE-PARENT VARIETIES IN HYBRID RICE

Drought is one of the important factors limiting crop production and becoming more and more severe in many regions of the world. Rice (Oryza sativa L.), as a paddy field crop, is particularly sensitive to drought stress. It is estimated that 50% of the world rice production is influenced more or less by drought. Breeding large panicle rice has become one of main targets for super hybrid rice breeding in China, and drought is the direct cause leading to low and instable seed setting rate of them and limits the production potential to full play. Previous research concluded that rice was more sensitive to water stress during meiosis stage. This study was conducted in 2013 cropping season at the Agricultural College of Yangtze University (30°20′N,112°13′E). 21 large panicle rice varieties were selected as materials, and sowing times were arranged according to accumulated temperature and 25 days after sowing, the seedlings were transplanted in to plastic buckets and kept soil water content 40%-50% from the initial of meiosis stage for 10 days as drought treatment. The objective of the study was to screen and identify drought resistant cultivars under the drought stress condition. Seed setting rate and total grains per panicle were investigated and drought resistance index and relative injured rate were calculated and the drought resistance of 21 rice varieties was evaluated by subordinative function value. The results showed that seed setting rate and total grains per panicle of all selection varieties were decreased under drought stress conditions, and the rice varieties with high resistance to drought had lower decreasing extent than the varieties sensitive to drought. Based on the values of subordinate function, 21 large panicle rice varieties were classified into three types, high drought resistant, resistant and the sensitive. The mean decrease extents in seed setting rate and total grains per panicle of high resistance varieties were 8.69% and 11.48%, and those of sensitive varieties were 5190% and 2815%. R527 and 9311xuan among high resistance varieties showed better performance in the seed setting rate and total grains per panicle under drought stress, and the relative injured rates were 016% and -217%, respectively. R527 and BL006 were selected for further pollination characteristic analysis, the sensitive variety BL006 showed significant decrease in anther length, the pollinated pollens per stigma, the germinated pollens per stigma and the pollen germination rate per stigma and the high resistance variety R527 decreased a little. In this research, the change extent of seed setting rate as not completely consistent with that of total grains per panicle, and these changes were important response to drought stress. Therefore, a joint indicator of seed setting rate and total grains per panicle may be better than only seed setting rate as index for drought resistance screening and identification in large panicle rice, and anther length and pollen germination rate per stigma could be chosen as reference indicators for pollination characteristic analysis, and the difference of drought resistance was closely related with the formation and vitality of male gametes