Study On Native Walnut Germplasm Resources Survey And Tree Selection In Mabian

In this study, walnut germplasm resources survey, including origin conditions (lacation, the household names, habitat, tree age, operation and management), growth conditions (tree vigor, tree stance, tree shape, tree height, crown width, branch height, diameter at breast height), leaf and fruit characteristics, phenophase(flowering&fruiting, flower and fruit drop period),seed status (fruiting branches rate, production situation, fallen fruit circumstances, nuts shape,nuts size, kernel color), has been made in Mabian County. Given that, morphometric indicators (nut high,abdominal diameter, DBH, nut weight, shell thickness, shelling rate) and seeds inclusions (crude fat, crude protein) have been measured and analyzed after repeat survey and sampling. And according to the different use of target selection of walnut. A germplasm nursery has been established for Teaching and Research Base of Sichuan Agricultural University in Chongzhou,and plus trees have been grafted propagation. After observing walnut early traits and evaluation, the conclusions are as follows:(1) Walnut is widely distributed in Mabian. Walnuts are distributed in19towns in Mabian County,and concentrated in Jianshe, Suba, Yuanjiaba, Qiaoba, Laoheba, Muzhu, Dazhubao, Xiaxi, Rongding, Shiliang, Shaqiang, Meiziba, Sanhekou, Gaozhuoying, Laodong and other towns.(2) Utilization of walnut resources rate in Mabian county is low. Most native walnut are non-fruit, more than76%of the total number of walnuts in Mabian.Only4.7%of the farmers make advantage of local high-quality walnut germplasm resources by grafting, while more than95%of farmers plant local seedlings or purchase foreign walnut seed.(3) Walnut variation types of Mabian county is diverse.Walnut form in Mabian is usually round, a few oval, the fruit high is2.4cm～4.7cm, fruit diameter is2.4cm～4cm, fruit weight is3g to17.9g, shell thickness is0.4mm～2.5mm, the kernel rate is24.9%～73.6%, the fat content is26.7%～67.7%, and the protein content is12.7%～～19.3%. Considering the high-quality and difference significant,Mabian walnut can be used as a rich germplasm resource walnut breeding research.(4) According to the different use objectives,Mabian walnuts were selected different indexes to be assigned respectively according to leisure food class, fruit class, nuts class, oil class, then we calculated the weighted average.We choosed fist ten of the superior tree of each taye as the finasuperior tree:Leisure food class:090614,060912,06122,090610,15094,09074,06094,110613-2,040318,07033。Ruit class:10106,04013-3,01117,07031,110815,06099,01099,04011,10109å'Œ100614。Nuts class:10106,07098,19043,060915,060214,060912,01034,040113,01096,04013。Oil class:01116,01117,10126,19047,10125,04092,100725,110613-1,111110,19048。The three champion trees10106,01117and060912are chosen to compete for two types of champion trees at the same time. And finally only01117got reserved.(5) According to breeding objectives and save situation of the superior tree and the expert opinions,090614and01117were selected as the final breeding results.