Effects of Different Gene-Cytoplasm Systems on Quantitative Characters in Reciprocal F2 Crosses of Maize (Zea mays L.)1
- Paul L. Crane and
- W. E. Nyquist2
The inbred WF9 genotype was incorporated into 41 diverse cytoplasms by backcrossing 4 times. Cytoplasmic donor lines were thus formed with largely WF9 genotype in cytoplasms of diverse origins. Seventeen of 60 reciprocal plant-to-plant F1 crosses between donor lines and 2 inbred testers gave significantly different yields in 1962. Subsequent experiments utilized reciprocal F2 pairs to eliminate maternal seed effects. Six of 16 reciprocal F2 pairs gave significant differences in yield in one experiment. In a more extensive study with 11 cytoplasmic donor lines plus the original WF9 crossed with 4 tester inbreds, the F2 pairs were tested 2 years at 2 locations. Fed reciprocal differences and interactions with reciprocals were significant for yield of grain, percent moisture at harvest or lodged plants at harvest. Only 2 of 48 differences between reciprocal crosses were significant for yield. However, 2 of the 4 overall mean reciprocal differences for testers were significant, and in these cases exotic cytoplasms were superior.
Cytoplasmic and genotype ✕ cytoplasmic interaction effects on the three characters as measured in reciprocal F2 hybrids were of low magnitude and probably interacted with years and locations. The results give little encouragement to the breeder to select cytoplasms with superior performance over years for even a limited region.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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