棉 花 学 报 Cotton Science 2009，21(1)：77-80
Genetic Analysis of Combining Ability and Heterosis between Bt Varieties and Non-Bt Ones in Upland Cotton ( Gossypium hirsutum L.) Abstract：The objective of this study was to determine if there was heterosis between Bt and not-Bt cotton ( Gossypium hirsutum L.) and to analyze their combining ability. 24 hybrids F1 were studied between six Bt varieties and four non-Bt ones in an incomplete diallel crossing design (NC Ⅱ ). The hybrid F 1 showed an appreciable heterosis. All 13 characters measured had mid-parent heterosis, nine of which showed higher performing parent heterosis and 11 expressed check heterosis. Combining ability analysis indicated that boll number per plant, boll weight, fiber length, fiber elongation rate and micronaire value were mainly controlled by gene additive effect, while seed cotton yield and lint yield were affected by non-additive effect, respectively. SCRC 17 was an excellent Bt transgenic cotton with insect-resistance and Jimian 12 was an acceptable non-Bt variety with better general combining ability. Among the 24 combinations, SCRC 17 × CCRI 12 showed apparent advantage in many agronomic traits. However, it was difficult to improve fiber quality through heterosis.
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