钟萼木一年生苗木生长分化与分级标准理论依据的探讨

Study on the growth character of differentiation and theoretical foundation of grading standard of 1-year nursery of Bretschneidera sinensis Hems1.

所调查的钟萼木苗木属于天然杂交种,苗木的高与地径生长性状遵循数量性状遗传.应用大样本抽样调查法和“正态分布标准差分类法”分别进行苗木地径、苗高生长量的调查与分类,分类统计结果表明:苗木群体高与地径性状生长类型权重呈正态分布,分别分布于(13,92)cm、(0.28,2.30)cm区间,一年生苗木高与地径生长量表现大的生长差异,直接影响个体后期生长.笔者提出应用“正态分布标准差分类法”作为理论依据划分该树种苗木等级标准,根据遗传学原理,认为苗高与地径年生长量在平均值类型以下的苗木属于遗传品质差的,确定为不合格苗;年生长量在平均值类型及以上的具有较好的遗传品质,可作为培育个体,确定为合格苗.在合格苗中,确定苗高与地径年生长量达平均值类型为Ⅱ级苗、平均值类型以上苗木定为Ⅰ级苗或优质苗.以该树种试验苗木高与地径年生长量确定苗木等级标准为:高年生长量在[33,43)cm、地径年生长量在[1.0,1.24)cm区间的苗木定为Ⅱ级苗;高年生长量在[43,53)cm、地径年生长量在[1.24,1.48)cm区间的苗木定为Ⅰ级苗;高年生长量在[53,73)cm、地径年生长量在[1.48,1.72)cm区间的苗木定为优质苗;高生长大于73cm、地径生长大于1.72cm的苗木为特级苗.文中首次利用遗传学与数理统计客观地确定苗木分级标准,该苗木标准保留较好的遗传品质个体,去除了不良遗传品质类型个体,可为苗木等级划分与遗传品质改良提供理论参考.

The test breed of Bretschneidera sinensis Hems1.belongs to the natural hybrid seed and the growth character of the height and caliper of breed follows the heredity of quantitative character.The investigation and classification were conducted with the large-sample investigation and“the standard deviation classification method of normal distribution”.The results indicated that the growth-type weight of the height and caliper of breed was Gaussian distribution and respectively distributed in(13,92)cm,(0.28,2.30)cm and the growth character of height and caliper was different and influenced the late growth of individuals.The grade stands of 1-year breed of Bretschneidera sinensis Hems1.was put forward according to“the standard deviation classification method of normal distribution”and the theory of genetics and the unqualified and qualified breeds was confirmed by the results that the breeds of nuder average value types were inferior and the breeds of average value type and upper average value type were genetically qualify.The average value type of the height and caliper growth of breed was confirmed as the gradeⅡbreed and the upper average value types of the height and caliper growth of breed were confirmed as the breed of gradeⅠor high grade within these qualified breeds.The grade standard was that the breeds of the height growth within[33,43)cm and the caliper growth within[1.0,1.24)cm were confirmed as the gradeⅡbreed;the breeds of the height growth within[43,53)cm and the caliper growth within[1.24,1.48)cm were confirmed as the gradeⅠbreed;the breeds of the height growth within[53,73)cm and the caliper growth within[1.48,1.72)cm were confirmed as the high grade breed;the breeds of the height growth over 73 cm and the caliper growth over 1.72 cm were confirmed as the special grade breed according to the height and caliper growth of the test breed.The grading standard of breed was objectively confirmed and put forward with the theory of genetics and mathematics in this paper and the grade standard of breed will reserve the excellent genetic individual and wipe out the inferior genetic individual and provide the theory reference for grading breed and improving heredity.