同時進行族羣內與族羣間改良對玉米產量雜種優勢之改變

Changes in Heterosis of Maize Populations as Affected by Three Cycles of Combined Intrapopulation and Interpopulation Improvement

盧煌勝(H. S. Lu)

《中華農業研究》 38卷3期 (1989/09) Pp. 306-311

https://doi.org/10.29951/JARC.198909.0003

摘要

在高產環境下，利用BS10及RSSSC兩個玉米族羣進行兼顧族羣內及族羣間改良之相互輪迴選拔。族羣內之改良包括多種葉病、莖腐病等抗病性之外表型混合選種及S1系統在高產環境下之產量評估。族羣間之改良則包括測交系統在高產環境下之產量試驗及選拔。三個循環之選種效應評估，分別利用族羣、族羣雜種及族羣測交種等，於四個不同環境下進行產量試驗。本試驗結果顯示：族羣本身、族羣雜種以及族羣測交種之子實產量之改良效果頗爲顯著。子實產量之雜種優勢估值以族羣雜種(F1)與二親本族羣平均(MP)差表之，在C0、C1、C2及C3分別爲1.33、1.49、1.04及0.90噸／公頃。子實產量雜種優勢以100×(F1-MP)/MP表示，在C0爲15.45%；在C1僅少許變化(15.69%)；在C2及C3則明顯降低爲10.06及8.13%。此種雜種優勢弱化之現象或許受族羣中顯性基因頻度減少所影響。爲避免雜種優勢之繼續弱化，選拔方式宜作適當調整。在S1系統及測交系統評估之同時，更加強調測交系統產量之重要性，對提高族羣雜種之選種效應與雜種優勢，應當有所助益。

並列摘要

A selection program using reciprocal recurrent selection procedures in maize (Zea mays L.) was developed. Intrapopulation and interpopulation selection procedures were used for two maize populations BS10 and RSSSC. Intrapopulation selection procedure included phenotypic mass selection for multiple leaf and multiple stalk-rot disease resistance and S1 family selection for grain yield in a high-yield environment. Interpopulation improvement involved selection of testcrosses of S1 family x inbred tester in a high-yield environment. Evaluation of populations per Se, population crossses and populations x testers for response to three cycles of selection for grain yield were conducted at four environments. The results indicate that selection response was satisfactory in populations per se, population crosses and populations x testers for grain yield. Heterosis estimates for grain yield calculated as differences between population crosses (F1) and midparents (MP) were 1.33, 1.49, 1.04 and 0.90 Mg ha^(-1) for C0, C1, C2 and C3, respectively. Heterosis calculated in 100×(F1-MP)/MP showed midparent heterosis in C0 was 15.45%. Subsequently, only a small change in C1 (15.69%), but a large reduction in C2 and C3, which were 10.06 and 8.13%, respectively. This reduction may indicate a decrease in the frequencies of dominant genes. Greater emphasis on testcrosses than on S1 families performance in this selection program is required to obtain better heterotic response.