一个低糊化温度水稻突变体(Mgt-1)的培育与稻米品质特征研究

在籼型细胞质雄性不育保持系Ⅱ 3 2B干种子经 3 0 0Gy60 Coγ射线辐照照育成的多种叶色突变系中 ,经稻米品质测定 ,筛选到 1个叶色黄化的低糊化温度突变体 ,定名为Mgt 1。稻米用 1 7%KOH处理 ,测得对照Ⅱ 3 2B的碱消值为 2级左右 ,而Mgt 1达 6～ 7级。Mgt 1的表观直链淀粉含量 (AAC)为 2 5%左右 ,与对照Ⅱ 3 2B差异不显著。用粘度速测仪 (RVA)测得的Mgt 1的米粉粘滞性谱 (RVA谱 )与对照Ⅱ 3 2B的存在一定差异 ,Mgt 1的消减值 (SBV)变小 ,热浆粘度 (HPV)显著变大 ,崩解值 (BDV)和回复值 (CSV)显著变小 ,但最高粘度 (PKV)和最终粘度 (CPV)基本相仿。Mgt 1的发现将为研究GT特性的物质基础及遗传特征提供理想的材料。

DEVELOPMENT OF A LOW GELATINIZATION TEMPERATURE MUTANT(Mgt-1) OF RICE AND ITS GRAIN QUALITY CHARACTERS

A low gelatinization temperature (GT) rice mutant is developed by treatment on dry seeds of an indica cytoplasmic male sterile(CMS) maintainer Ⅱ32B with 300Gy of 60 Co γ\|rays,and named as Mgt\|1.The mutant is also a leaf color mutant which shows lifetime yellow leaves.The cooking and eating quality characters of Mgt\|1 and Ⅱ32B were analyzed.The ASV(Alkali Spreading Value) of Ⅱ32B is about 2～3 in a 2～7 score system,while that of Mgt\|1 is up to 6～7 when treated with 1\^7% KOH.Mgt\|1 has AAC(Apparent Amylose Content) of about 25%,with no significant difference from that of Ⅱ32 B.The RVA profiles of Mgt\|1 and Ⅱ32B are different in some characters.The PKV(Peak Viscosity Value) and CPV (Cool Paste Value) of Mgt\|1 is similar to,SBV(Setback Value)smaller,and HPV(Hot Paste Value) bigger than that of Ⅱ32B.Consequently the BDV(Breakdown Value) and CSV(Consistence Value) of Mgt\|1 was markedly less than that of Ⅱ32B.The above results implied that the GT character could be improved by mutation induction without changing its AAC.Mgt\|1 will also serve as an ideal material for studying substantive basis and heredity characteristic of GT.