Study On The Difference Of Fruit Quality And Seedling Growth Characteristics Of Different Chestnut Varieties In Hunan

Chestnut(Castaneamollissima Blume)is one of the most important woody food crops in China.It is drought resistant and barren.It is known as iron crop".It is widely planted in China,from Jilin in the north to Hainan Island in the south.Under different climatic conditions or topographical conditions,Chinese chestnut has formed a batch of regional improved varieties.Hunan is one of the southern Chinese chestnut.After the introduction of the improved varieties of tienitou and nine varieties in the 1990s,the selection of improved varieties in this region has been lagging behind.In this paper,starting from the process of improving the variety of Chinese chestnut,through the optimization of 10 varieties in different areas,taking the iron head as a reference,the variety comparison experiment and the 1-year-old growth comparison experiment of the tested varieties were carried out.By combining field investigation with laboratory operation,the differences of appearance quality and internal quality of different varieties of Chinese chestnut were analyzed.At the same time,the growth rules of 1-year-old grafted seedlings were made The differences of law,leaf physiology and photosynthetic characteristics were investigated and analyzed,so as to select excellent chestnut varieties as the breeding objects.(1)The fruit appearance quality of Linxiang No.1 chestnut was longer,wider and thicker with bracts,82.06mm,59.89mm and 62.06mm,respectively;that of Shimen chestnut was 36.39mm and 25.02mm,respectively,and that of Linxiang No.2 chestnut was the largest,28.52mm;that of melt chestnut was 3.50mm and that of iron head was the largest The thickness of chestnut bract is the smallest,only 2.88mm;the length of chestnut bract thorn of Chengbu chestnut is the largest,reaching 17.76mm,and Xintian chestnut is the smallest,only 12.23mm;Huaqiao chestnut and Rongshui chestnut are the largest,reaching about 1.45mm,and iron head is the smallest,only 0.76mm;iron head is the highest,7.13%,xintianban The crude fat content of chestnut is the lowest,only 5.45%;the soluble sugar content of Shimen chestnut is the highest,14.68%;Xintian chestnut is the lowest,only 3.08%;the starch content of Linxiang 2,Anhua,Linxiang 1 and Chengbu chestnut is about 55%;the starch content of melt water chestnut is the lowest,only 40.64%;the crude protein content is about 55%Among them,Shimen chestnut had the highest crude protein content(10.39%).Huaqiao chestnut had the lowest crude protein content(6.79%).(2)The growth trend of Chestnut Seedling is "s" curve.From the beginning of May to the beginning of September,the ground diameter of Linxiang No.1 chestnut grows the fastest,reaching about 1.78cm at the beginning of September,and then the ground diameter of Huaqiao chestnut keeps growing fast,reaching 1.42cm at the beginning of September and growing fast from the beginning of September to the end of September The growth period lasts for a short time,only about 20 days,but at the later stage of growth,there is a big difference in the ground diameter growth among varieties.After the rapid growth period,that is to say,at the end of September,the height of one-year-old chestnut seedlings is the largest,158cmand 157cm,respectively.The height of Huaqiao and Xintian chestnut varieties is the smallest,only 110cm and 109cm,entering the later stage of growth After that,the growth of one-year-old Chestnut Seedling Height tends to be slow;the change trend of protein content of different chestnut varieties is basically similar,the protein content in the early growth stage is higher,and the protein content in the late growth stage rapidly decreases,but the protein content of No The activity of nitrate reductase in the growing leaves increased gradually,and it was the biggest in the later growing stage,which was 301μg·g-1·h-1 and 268.29μg·g-1·h-1,respectively;the leaf weight and length of Linxiang No.1 and Xintian chestnut were the biggest,which were 0.037g·cm-2 and 0.034 g·cm-2,which were 27.2cm and 26.3cm,respectively.From the overall analysis,the differences between leaf weight and leaf width were found Only Chengbu chestnut,Anhua chestnut,Shimen chestnut and tierentou chestnut are the opposite.(3)At the early stage of growth,the photosynthetic rate of Chengbu chestnut variety,the best chestnut variety in the forest farm and Anhua chestnut variety was the highest.Under the high temperature and high humidity climate in September,Chengbu chestnut variety and Linxiang No.2 chestnut variety had the highest photosynthetic rate and showed strong adaptability.The leaf transpiration rate of different chestnut varieties showed strong vitality and showed the most outstanding performance in August,while that of melt water chestnut variety was the highest The transpiration rate of Xintian chestnut was the lowest,only 6.79umolH2O·m-2 · s-1 and 8.99umollH2O·M-2·s-1.The transpiration rate of most chestnut varieties increased in the late growth period.The change of leaf stomatal conductance of different chestnut varieties was also prominent in August,but that of Linxiang No.2 chestnut was the highest in the late growth period of October.