The Interspecific Crossability Of Buckwheat And The Yield And Trait Analysis Of Hybrid F1 Among Species

The yield of cultivated sweet buckwheat was greatly limited due to its heterotypic style and self-incompatibility under natural conditions.Wild sweet buckwheat and Tartary buckwheat are isostyle buckwheat,which has the character of self-crosslinking.The yield of cultivated sweet buckwheat could be greatly improved if the isostyle self-crossable genes of wild sweet buckwheat and Tartary buckwheat could be introduced into cultivated sweet buckwheat by hybridization.However,wild sweet buckwheat and Tartary buckwheat are distant species of sweet buckwheat.In this experiment,interspecific hybridization of cultivated sweet buckwheat with wild buckwheat and Tartary buckwheat was carried out.The growth dynamics of pollen tube during fertilization was observed by fluorescence microscopy.Through in vitro culture of hybrid ovary,embryo rescue of dying hybrid embryo was carried out,and suitable technical system of embryo rescue of buckwheat hybrid was explored.At the same time,the heterosis of cultivated sweet buckwheat varieties was studied.The aim of this study is to investigate the pollination mechanism,embryo saving technology and heterosis utilization of distant hybridization in buckwheat.Research findings:(1)During 44 combinations only Dingtianqiao(pin style and thrum type)x Ye Sheng Tian Qiao,Bei Zao Sheng(pin style)x Ye Sheng Tian Qiao and TQ12-08(pin style)x Ye Sheng Tian Qiao are fruitful,the rest of the combinations aren't fruitful,Ye Sheng Tian Qiao are all male parent of these three combinations,so it can be judged that combinations with cultivated common buckwheat as the female parent and wild common buckwheat as the male parent may have the strongest crossability.The cross pollination between cultivated and wild common buckwheat by repeated pollination could improve the fecundity to some extent,but it due to the combination.(2)When the Ye Sheng Tian Qiao was used as the male parent,the pollen tube could normally elongate and enter the embryo sac to complete fertilization after pollination.After male pollination,the pollen tubes of other Tartary buckwheat were inhibited from growing and could only extend to about 1/3 to 1/2 of the style.Common buckwheat as female parent and Ye Sheng Tian Qiao as male parent,although can normal pollen tube growth in the embryo sac,have different fecundity with different female parents,the results shows that there is incompatibility before and after fertilization in distant hybridization of buckwheat.The effect of repeated pollination and stigma treatment with 2,4-d at 1h after pollination was not obvious,and the pollen tube did not grow further.The stigma was treated with 2,4-d solution 1h before pollination to make the pollen tube grow longer,but still not long enough to stretch the pollen tube into the embryo sac for fertilization.(3)Most hybrid embryos obtained after interspecific hybridization would die,and embryo rescue was conducted for hybrid embryos about to die.The most appropriate time for the ovary of explants was 8d after pollination,and the most appropriate medium composition was MS+6.0mg/L 6-ba +1.0mg/L IAA+3.0% sucrose +0.7% AGAR;The hybrid F1 seeds of Dingtianqiao1×Ye Sheng Tian Qiao were planted.After observing the plant morphology and floral apparatus characteristics at the mature stage,the plant could be determined as a true hybrid plant;(4)The dominance of economic traits,such as plant height,main stem node number,main stem branch number,flower cluster number per plant and 1000-seed weight,are different in the 12 self-cross bred hybrid species,after comprehensive comparison,hybrid 5-2,hybrid 4-2 and hybrid 3-2 and hybrid 2-1 are selected as strong dominant hybrid combinations.