玉米測交與全互交分析

Abstract

本試驗使用7 個熱帶型抗露菌病王米自交系，進行全互交，並各自為母本與到固分別代表熱帶沿海平原硬粒種、美國溫帶馬齒種及古巴硬粒種的優良自交系檢定親進行測交，以分析自交系組合力，探討高產玉米雜種組合模式，並探討產量與8 個農藝性狀間的關係，以供選育高產親本與雜種組合的參考。 測交檢定結果，母本與父本的產量及8 個農藝性狀的一般組合力均有極顯著的差異；母本與一父木約交感效應，則除株高、穗位高：葉面積及收穫時子粒含水率外，差異均不顯著。大多數的熱帶型自交系與美國溫帶型馬齒種自交系檢定親Hi 26 的雜種組合獲有較高的產量，顯示溫熱帶兩型種源間存有良好的雜種優勢模式可資利用。 全互交分析結果顯示，雜種的產量及8 個農藝性狀之一般組合力亦均有極顯著的差異；但特定組合力僅限於子粒產量及開花期兩性狀。一般組合力均大於特定組合力。抗露菌病自交系Narino 330 及SR 52M 在子粒產量及其他農藝性狀上均有很高的一般組合力效應，為可用於選育高產雜種玉米的優良自交系。 全互交結果亦顯示硬粒種與馬齒種間雜交存有較大的雜種優勢，而馬齒種與馬齒種則以不同來源也可獲有良好的組合。 子粒產量及8 個農藝性狀間均有極顯著的正相關，表示雜種的產量與中晚熟性、較大株型、及較大子粒等性狀有密切關係。雜種親本中最早熟的自交系PH9，即因其株形較小，雜種產量亦最低。 Seven DMR maize inbreds were analyzed in a diallel set, and also crossed as maternal parents to three elite inbred testers to estimate combining ability, heterosis pattern, and the correlation among yield and eight other traits for rapid use of high yield exotic germplasm. Testrcoss analysis indicated that general combining ability was highly significant for yield and eight other traits in maternal and in paternal groups. Maternal x Paternal interaction was nonsignificant except for plant and ear heights, leaf area and grain moisture content at harvest. Most of the DMR inbreds tested had the best yielding in hybrid combinations with tester Hi26, representing a heterosis pattern of Tropical x Temperate germplasms. Diallel-cross analysis indicated that general combining ability was also highly significant for yield and eight other traits among 7 inbreds, but specific combining ability was only for yield and days to tasseling. GCA was more significant than SCA in these diverse germplasms. DMR inbreds Narino 330 and SR52M had significantly high GCA effects in yield and other traits, and were the best inbreds for rapid development of high yielding hybrids. Correlation coefficients among yield and eight other traits were all positive and highly significant, indicating that high yielding hybrids were always associated with medium to late maturity, taller plants, and greater kernel-sink capacity. The early maturing inbred PH9 was found to be the lowest in plant height and also in average grain yield performance.