杂种棉“苏杂16”的杂种优势及F2自交衰退

摘要

An interspecific hybrid of upland cotton，Suza 16，was selected asstudy materials to measure the heterosis and inbreeding depression of 14 traits of Suza 16 F1 and F2 in 1997～1998 successively．Experimental results indicated that：①The F1 heterosis in yield and yield components of lint cotton （with the exception of lint percentage）all showed extremely significant deviation，as compared with the mid-parent value and the check．Among those the hybrid vigor ratio of boll weight was superior to that of boll number per plant．In boll weight and its components，the heteroses of seed number per boll and seed setting efficiency were higher than those of other factors．In fiber properties，the middle parent heterosis and the useful heterosis of fiber strength were significant and extremely prominent，respectively．②Though the inbreeding depression was detected，the mid-parent and useful heterosis of Suza 16 F2 in yield and yield factors（exclusive of lint percentage）still reached 0.05 or 0.01 significant level．The heterosis of boll number per plant was higher than that of boll weight．The hybrid vigor of seed index was the dominant factor among those of all boll weight components．③Lint percentage of F1 and F2 both showed slight mid-parent superiority，but obviously lower than the check．Micronaire value was both prominently higher than the check while fiber uniformity was similar to those of parents and check．The heteroses of plant height of F1 and F2 exhibited extremely significant and significant deviation，respectively．④The higher the heteosis of F1 traits was，the larger the F2 inbreeding depression would be．⑤F2 generation was available when the parents were selected properly．%以陆地棉品种间杂交种“苏杂16”为材料，连续两年测定其F1、F2的14个性状的杂种优势和自交衰退率。结果表明：①苏杂16F1皮棉产量及其构成因素(衣分除外)的中亲优势与竞争优势均达极显著水平，其中铃重优势大于结铃数优势；铃重构成因素中单铃种子数和结籽效率的杂种优势极显著；纤维品质性状中，比强度中亲优势显著，竞争优势极显著。②苏杂16F2皮棉产量及其构成因素(衣分除外)的杂种优势虽存在衰退现象，但中亲优势与竞争优势仍达显著或极显著水平，其中铃数优势大于铃重优势；铃重构成因素中以子指的优势为主。③苏杂16F1、F2的衣分均具微小中亲优势，而竞争优势显著低于对照“泗棉3号”；纤维整齐度均与亲本及对照接近，麦克隆值的竞争优势均显著；F1、F2的株高杂种优势分别达极显著和显著水平。④F1杂种优势大的性状，其F2自交衰退率一般也较大。⑤只要亲本选配得当，F2是可以利用的。