Biological Characteristics Of Yichang Walnut Resources

In order to provide reference for the breeding and scientific and rational cultivation practice activities of the raw walnut resources in Yichang City,,Hubei Province,we use four local seedling walnut plants(numbered ZCP1702,ZCP1703-1,ZCP1703-2,and ZCP1708)as the test materials,to observe the biological characteristics of flowering,fruit drop dynamics,fruit growth dynamics and the change of fruit flavor substance content.The results are as follows:The blossom periods of the male and female flowers of the four local seedling walnut plants were in April,the blossom period of male flowers for every plant lasted for 9 to 15 days,the blossom period of female flowers lasted for 11 to 17 days,the full-bloom stage of the male and female flowers were relatively short,only for 3 to 5 days;ZCP1702 and ZCP1708 belong to protogynous protandrous type resources,ZCP1703-1 and ZCP1703-2 were female-type resources protogynous type resources;The pollen viabilities at full-bloom stage were the highest,the first-bloom stage the second,and the last-bloom stage the lowest.The pollen viabilities of the local seedling walnut plants at the full-blossom stage were over 40%.The physiological fruit drop dynamics for all plants showed two distinct peak periods,which respectively appeared in mid-May and mid-June and were basically consistent with the liquid state stage Inside the seed in time i.e.occured in the early stage of embryo development.The growth dynamics of fruit three-diameter,fruit core diameter,green skin thickness,fruit volume and weight of the four plants showed a dynamic trend of first fast and then slow.The growth process of the fruit is divided into a rapid growth phase and a slow growth phase.The three-diameter,fruit-nuclear transverse diameter and green skin thickness reached the maximum growth in early July,and the fruit volume and weight reached the maximum growth in mid-July;The development of the seed kernel went through liquid stage,gel stage and solidifying stage(cotyledon formation stage)in turn.The stages of the fruit core hardening and the seed kernels from liquid to solidification occured in the fruit rapid growth phaset,and both of them were substantially consistent in time.The dynamic changes of the contents in seed during the filling stage of seeds were as follows:The water content in the kernels showed a very significant downward trend;the fat content increased and the change range was large;The protein content is basically declining,but the decline is very small in early August and before;the soluble sugar content increased first and then decreased and reached the highest value in early August,but the content for all stages were not high,less than 1.5%;The polyphenols content from beginning to end changed little;The polyphenols content in seed coat was very high,but the content of seed kernel was very low.The seed coat is the part where walnut showsed astringent taste.