The objective of the present study was to establish the genotypic relationship between the chromosome 1 segment marked by the Adh1 locus and a number of agronomic traits. The study was carried out on Moldavsky 291, a high-yielding hybrid widely cultivated in Moldova. The parental lines, F1 and 188 F2 plants were estimate for the following quantitative traits: 1) time from emergence to the flowering of panicles, days; 2) time from emergence to the flowering of top ears, days; 3) time lag of the onset of flowering between panicle and top ear, days; 4) time from flowering to the maturation of top ears, days; 5) time from emergence to the maturation of top ears, days; 6) number of stems; 7) plant height, cm; 8) stem length, cm; 9) panicle length, cm; 10) top ear position on the stem, cm; 11) diameter of the bottom first internode, mm; 12) number of the above-ground nodes; 13) number of ears with kernels; 14) internode mean length, cm; 15) stem volume parameter, litre; 16) ratio of stem length to bottom first internode diameter; 17) weight of top ear at harvest, gm; 18) weight of the remaining ears at harvest, gm; 19) total weight of ears, gm; 20) the proportion of second top ears in total ear weight, %; 21) daily increment in ear weight, gm.
Enzyme electrophoresis extracts from pollen were run in 14% starch gel (buffer system "G", pH=7.0) (Wendel and Stuber, Isozyme Bull. 17:4-11, 1984). The gel staining was performed using reaction mixtures from Levites, EV' list (Genetika isozymes of the plants, Nauka, Novosibirsk, 1986).
Isoenzyme analysis has shown the parental lines to differ with respect to the Adh1 locus. This allows 3 genotype classes to be distinguished in the F2 population. For the quantitative traits studied, the following statistically significant differences between classes FF, FS, and SS were observed (Table 1): 1) panicles of the FS heterozygotes enter flowering earlier than those of SS; there is a larger time lag for the onset of flowering between panicle and ear compared with FF and lower weight of the first ear compared with FF; 2) the higher position of the top ear in the FF homozygote.
The results suggest that the chromosome 1 segment marked by the Adh1 locus genetically affects the above traits in maize. Future research is needed to ascertain the nature of the effects observed.
Table 1. Mean values of quantitative traits for three Adh1 segregation
classes in maize F2.
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