以广西野生蕉为父本的香蕉远缘杂交

Distant hybridization of banana based on Guangxi wild banana as male parent

【目的】以广西野生蕉为父本开展香蕉远缘杂交研究,为野生蕉资源抗寒、抗病等优良性状(基因)的开发及利用提供理论参考。【方法】以广西野生蕉LW和RF为父本,自主选育的金粉1号、35b号、30b号和32b号为母本组配8个杂交组合,统计各组合单株种子数、单果种子数及不同授粉梳序的单梳种子数和单果种子数等指标,分析雌花授粉梳序、雌花发育阶段和授粉时期对杂交组合结籽的影响。【结果】不同杂交组合间的杂交亲和性存在明显差异,以金粉1号为母本的杂交组合结籽情况整体较其他组合好,其中金粉1号×LW(L1组合)的单株平均种子数和单果平均种子数均最高,分别为142.0和1.980粒,其次为金粉1号×RF(R1组合),分别为73.0和0.896粒。8个杂交组合的单梳平均种子数和单果平均种子数从第1梳至第7梳整体上均呈先上升后下降的趋势,即中间梳序(第3和第4梳)单梳平均种子数和单果平均种子数较高,头两梳(第1和第2梳)和尾两梳(第6和第7梳)单梳平均种子数和单果平均种子数较低,除32b号×LW(L4组合)的头(第1梳)和尾(第7梳)两梳未获得种子外,其他杂交组合各梳序间均获得种子,各杂交组合不同梳序的单梳平均种子数和单果平均种子数均存在差异,其中以L1组合不同授粉梳序的单梳平均种子数和单果平均种子数最高,分别为12.318～36.001和0.712～2.081粒。于雌花发育第2阶段(雌花苞片与花蕾中轴间开张角度10°～80°)授粉,各杂交组合的单果平均种子数均较第1阶段(苞片与花蕾中轴间开张角度<10°)和第3阶段(苞片与花蕾中轴间开张角度大于80°之后)授粉的高。第Ⅱ时期(9—10月)授粉各组合的结籽株率和单果种子数均明显低于第Ⅰ时期(11—12月)授粉,说明较低气温不利于花粉萌发及受精。【结论】在实际生产中杂交授粉应选择中间梳序(第3和第4梳),当雌花苞片与花蕾中轴开张角度10°～80°时进行授粉的效果较好,且授粉时期应避开寒冷、潮湿的冬季。

【Objective】The study on the distant hybridization of bananas based on Guangxi wild banana as male parent was conducted to lay a foundation for the rational and efficient utilization of the excellent traits(genes)of wild banana resources against coldness and disease.【Method】Guangxi wild banana LW and RF were as the male parents,Jinfen No.1, No.35b,No.30b and No.32b,which were independently selected were taken as female parents. They were crossed into eight hybrid combinations. The seed number per plant and the seed number per fruit in each combination,the seed number per comb and seed number per fruit at each comb order were counted.The effects of pollination comb order,female flower development stage and pollination period on the hybrid combination seeding were analyzed.【Result】There were great differences in hybrid affinities between different hybrid combinations. The seeding condition of the hybrid combination with Jinfen No.1 as the female parent was the best. The combination of Jinfen No.1×LW(L1 combination)had the highest average seed number per plant and average seed number per fruit,which were 142.0 and 1.980 respectively. Followed by the combination of Jinfen No.1×R1(R1 combination),average seed number per plant and average seed number per fruit were 73.0 and 0.896 respectively. In the eight combinations,average seed number per plant and average seed number per fruit from the 1st comb to the 7th comb increased and then decreased as a whole,which meaned that the middle comb(the 3rd comb and the 4th comb)had high average seed number per plant and average seed number per fruit,the head combs(the 1st and 2nd combs)and tail combs(the 6th and 7th combs)had low average seed number per plant and average seed number per fruit. The head comb(the 1st comb)and tail comb(the 7th comb)of No.32b×LW(L4 combination)had no seeds,but other combinations at each comb order could obtain seeds. There was difference in average seed number per plant and average seed number per fruit among the comb orders of the combinations. The differences of average seed number per plant and average seed number per fruit of different combs of L1 combination were the largest,which were 12.318-36.001 and 0.712-2.081. When pollinated at the second period of female flower development(the opening angle between female flower bract and bud axis was 10°-80°),the average seed number per fruit of each combination was higher than when pollinated at the first period(the opening angle between female flower bract and bud axis was <10°)and the third period (the opening angle between female flower bract and bud axis was >80°). The seeding rate and seed number per fruit of the combinations pollinated at the stage Ⅱ(September-October)were largely lower than pollinated at stage Ⅰ(November- December). It indicated that low temperature was not beneficial for pollen germination and fertilization.【Conclusion】 When pollinating in production,the middle combs(the 3rd and 4th combs)should be selected. When the opening angle between female flower bract and bud axis was 10°-80°,the pollination effects are fine. Pollination should avoid polluting cold and humid winter. The optimal pollination period throughout the year needs follow-up study.