甘藷葉片同功異構酶帶型與若干性狀間相關性之分析

Analysis on The Correlation Between Isozyme Markers and Some Characters in Sweet Potato (Ipomoea batatas (L.) Lam)

本報告利用膠體電泳法分析35個甘藷營養系葉片四種同功異構酶之酶型，並研究這些酶型與一些性狀及塊根化學組成間之關係。所分析之酵素為黃遞酶（DIA），蘋果酸去氫酶（MDH），磷酸化酶（PP），與過氧化酶（PX）等，其中DIA可依條帶出現之位置與濃淡區分為兩型，而MDH則根據出現條帶數與移動速率之不同可區分為三型，PP則有具活性及活性極弱或無二型，在PX共有6區酶譜可各區分為2-4型。利用酶型相似度進行群叢分析亦顯示出大部分來源相同之品系其酶譜分布仍存在某種程度之歧異度；由這些可資分辨的酵素型與一些數量性狀（可販賣塊根數，可販賣塊根鮮重，不良塊根數，不良塊根鮮重與地上部鮮重等），及塊根之化學組成（乾物含量，蛋白質含量，糖含量，澱粉含量與纖維含量），利用單因子變方分析，進行每一酵素酶型與各性狀間關係之分析。分析結果顯示部份酶型與一些數量性狀有顯著的關係，例如DIA酶型與地上部鮮重，PXA1區酶型與塊根乾物含量，PXA2區酶型與塊根糖含量，PXA3區與地上部鮮重，而PXA4區酶型與最多的調查性狀有相關（不良塊根數，不良塊根鮮重，地上部鮮重，塊根蛋白質含量，糖含量及纖維含量等）。因此甘藷葉片DIA和PX之酶型，或有應用於甘藷種苗早期選拔：較少的不良塊根和地上部鮮重，較多的塊根乾物含量、蛋白質含量及糖含量之可能，值得更進一步深入研究，以增加甘藷育種速率。

Gel electrophoresis was conducted for the exploration of isozyme markers and studies on the correlation between isozyme markers and some characters of 35 clones of sweet potato (Ipomoea batatas (L.) Lam). Enzymes such as diaphorase (DIA), malate dehydrogenase (MDH), phoshporylase (PP) and peroxidase (PX), which indicated polymorphisms, were included. Two types of polymorphism were noted in DIA, and three in MDH. Presence and lack (or weak) of activity in PP were also observed. Zymograms of PX were divided into 6 distinct zones for classification. At least 2-4 variants were found at each zone. Cluster analysis based on genetic similarity of zymotyps was done. Some degrees of diversity were noted among accessions even from the same origins. Correlations between zymotypes and some quantiative traits (marketable root number, marketable root weight, cull root number, cull root weight, fresh weight of tops), and chemical composition of storage roots (contents of dry matter, protein, sugar, starch and fiber) were studied. From single factor ANOVA test for each enzyme zone to each measured trait, it is indicated that some zymograms were significantly correlated with some quantitative traits, i. e. DIA and top fresh weight, PXA1 and dry matter of storage roots, PXA2 and sugar content of storage roots, PXA3 and top fresh weight, and PXA4 with the most characters (cull root number, cull root fresh weight, top fresh weight, protein, sugar and fiber contents of storage roots). Therefore, it is suggested that DIA and PX zymograms of sweet potato leaves may be utilized in selecting breeding lines with less cull root number, less top fresh weight, higher dry matter, protein and sugar contents of storage roots in the early stage of breeding. It deserved further research to increase breeding efficiency of sweet potato.