瓠瓜砧木嫁接西瓜苗对枯萎病的抗性综合评价

目的]分析不同瓠瓜砧木西瓜嫁接苗对西瓜枯萎病的抗性表现及生长、生理指标差异,确立评价抗病性关键指标,为筛选砧用瓠瓜及抗病育种提供参考.方法]选用6份不同类型的瓠瓜(H04、H05、H07、H10、H0405和H1004)为砧木嫁接西瓜栽培品种,以西瓜栽培品种自根嫁接苗为对照,采用苗期人工接种尖孢镰刀菌西瓜专化型2号生理小种鉴定瓠瓜砧木嫁接苗的抗病性,测定嫁接苗的株高、茎粗、最大叶片叶面积、叶绿素含量(SPAD值)及叶片过氧化物酶(POD)活性、丙二醛(MDA)含量等生长、生理指标,采用隶属函数法综合评价不同瓠瓜砧木嫁接苗对枯萎病的抗性.结果]不同瓠瓜砧木嫁接西瓜苗对枯萎病的抗性表现不同,砧木H0405和H04的嫁接苗表现高抗,其最大叶片叶面积和叶绿素SPAD值最高,株高和茎粗增长较快,叶片POD活性显著高于自根嫁接苗(P<0.05,下同),MDA含量显著低于自根嫁接苗.以生长、生理指标的隶属函数值综合评价不同类型瓠瓜砧木嫁接西瓜苗的抗病性,排序结果与按株高、最大叶片叶面积、叶绿素SPAD值的大小排序和以病情指数鉴定抗病性的结果基本相同.结论]瓠瓜高代自交系H04可作为抗西瓜枯萎病的砧用瓠瓜育种资源,其杂种一代H0405可作为抗西瓜枯萎病的优良砧木.通过测定嫁接苗的株高、最大叶片叶面积和叶绿素SPAD值可快速评价嫁接苗对西瓜枯萎病的抗病性强弱.

Comprehensive resistance evaluation of grafting watermelon seedlings on different bottle gourd stocks to watermelon fusarium wilt

Objective]In the present study, resistance of grafting watermelon seedlings on different bottle gourd stocks to watermelon fusarium wilt and the differences in growth and physiological indexes were analyzed, key indexes for evaluat-ing disease resistance were established, in order to offer reference for selecting bottle gourd stocks and resistant variety breeding. Method]Grafting watermelon seedlings on six different bottle gourd stock types(H04,H05,H07,H10,H0405 and H1004) were taken as materials, and self-grafted watermelon seedlings were used as control. Disease resistance of grafting watermelon seedlings on bottle gourd stock was identified through inoculation of Fusariumoxysporum f. sp. niveum on graft-ing seedlings. Plant height, stem diameter, maximum leaf area, leaf chlorophyll content(SPAD value), leaf peroxidase (POD) activity, and leaf malondialdehyde(MDA) content of grafting watermelon seedlings were determined. Resistance of different grafting seedlings to watermelon fusarium wilt was evaluated by subordinate function. Result]Different grafting seedlings presented different resistance performance to watermelon fusarium wilt. The seedlings grafting on H0405 and H04 showed high resistance. These seedlings had the largest maximum leaf area and highest SPAD value. The growth of plant height and stem diameter was fast. Leaf POD activity of the seedlings was significantly higher than that of self-grafted wa-termelon seedlings yet MDA content was significantly lower than that of self-grafted watermelon seedlings(P<0.05). Sub-ordinate function based on growth and physiological indexes was adopted to comprehensively evaluate disease resistance of grafting watermelon seedlings on different bottle gourd stocks. The results were in accordance with the results based on rank of plant height, maximum leaf area, SPAD value and disease index. Conclusion]High generation inbred line H04 can be breed-ing resource of bottle gourd as stocks with high resistance to watermelon fusarium wilt. Its first generation of hybrid H0405 can be good stock for watermelon with high disease resistance to watermelon fusarium wilt. Height, maximum leaf area and leaf chlorophyll content(SPAD value) of grafting seedlings can be useful indexes to evaluate resistance to watermelon fusarium wilt.