Genetic Variability on Tolerance of Maize (Zea mays L.) Genotypes Induced with Sodium Azide Mutagen
Genetics and Molecular Biology Unit, Department of Botany, University of Ibadan, Ibadan, Nigeria
Molecular Plant Breeding, 2017, Vol. 8, No. 3 doi: 10.5376/mpb.2017.08.0003
Received: 25 Feb., 2017 Accepted: 17 Apr., 2017 Published: 24 Jun., 2017
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Preferred citation for this article:
Olawuyi O.J., and Okoli S.O., 2017, Genetic variability on tolerance of maize (Zea mays L.) genotypes induced with sodium azide mutagen, Molecular Plant Breeding, 8(3): 27-37 (doi: 10.5376/mpb.2017.08.0003)
This study investigated the mutagenic variability of maize (Zea mays L.) genotypes induced with sodium azide (NaN3). The seeds of maize genotypes; TZE-WDTSTR C4, TZM 154, SAMMAZ 15, DTE-YSR BC3, EV99 QPM, DTSR COF2, TZM 146 and TZM 1441 were pre-soaked in distilled water for six hours before treated with 20ml of sodium azide at 35, 45, 55, and 65 mM for six hours. The untreated maize served as control. The seeds were sown on perforated polythene bags containing 7kg of soil with three replicates in a complete randomized design. The observations from seedling to maturity recorded albino, xantha and viridis mutant traits. The mitotic studies carried out on the root tips of the seedlings revealed chromosomal aberrations such as abnormal anaphase and metaphase and chromosomal deletion. There were variations among the genotypes for yield, morpho-agronomic traits and mutation tolerance. TZE-WDTSTR C4, TZM 154 and TZM 146 were early maturing genotypes. TZM 1441 and EV99 QPM were the most tolerant genotypes to mutagenic effect, while EV99 QPM performed best for percentage seed germination, ear aspect, husk cover and mutation tolerance. The mutation tolerance was positive and strongly correlated with agronomic and yield traits (days to first tasseling, tasseling length, plant stand, ear aspect, husk cover and number of cobs) compared to growth traits. The number of cobs produced is positive and strongly related with mutation tolerance at r = 0.77; p < 0.01, while the ear aspect is positive and strongly associated with husk cover, number of cobs and mutation tolerance at r = 0.86, 0.76 and 0.79 respectively. The first Principal Component Axis (Prin 1) had the highest contribution to the variation of morphological, yield and mutation tolerance traits with proportion and Eigen value of 23.12% and 3.24 respectively, while Prin 14 had the least contribution. Stem height, grain weight, shoot biomass and root biomass were closely related to mutation tolerance in Prin 1 than other traits. Therefore, selection of the most tolerant genotypes to sodium azide (chemical mutagen) should be considered in breeding programmes.
Maize genotypes; Variability; Mutagenic tolerance; Sodium azide