Thuan, Nguyen Dat (2011) Expression and inheritance of traits in wild mungbean (Vigna radiata ssp. sublobata) x cultivated mungbean (v. Radiata ssp. radiata) hybrids. Masters (Research) thesis, James Cook University.

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Abstract

Mungbean (Vigna radiata (L.) Wilczek ssp. radiata) is an economically important crop in Asian countries where breeding research is being undertaken to improve varietal adaptation, yield and seed quality. The wild mungbean (ssp. sublobata) is a potentially useful adjunct to breeding, as the wild accessions possess traits that confer adaptation in their natural environments. The wild accession ACC 87 collected near Townsville has been identified as being perennial, a potentially useful trait for forage crop improvement. Accession ACC 1, from Mackay is very late flowering and was reported to possibly have a long juvenile (LJ) trait similar to that found in soybean. Before these and other potentially useful wild traits can be exploited, information is needed on their inheritance. Therefore, a study was conducted to examine the inheritance of traits in four hybrid cultivated X wild mungbean populations. The study examined the expression of traits in the parental plants, and the F1, F2, BCP1 and BCP2 progeny generations, when grown under controlled conditions in pots. The four genetic populations had been created by hybridizing using two cultivated mungbean varieties, Berken and Kiloga, with each of two wild parents, ACC 1 and ACC 87.

Several morphological traits, including lobed leaflet shape, seed testa and hilum color, and plant habit were found to be under simple (qualitative) genetic control, with the wild type generally dominant. An exception was putative resistance to powdery mildew infection in the wild accessions, which appeared to be recessive. Many other traits like phenology, nodes per plant, seed yield and biomass were under quantitative genetic control. The perenniality trait in ACC 87 appeared to be under simple genetic control, with expression of perenniality due to two dominant complementary genes. In contrast, flowering in the two ACC 1 populations appeared to be quantitatively inherited, with no evidence of a LJ trait. There were many similarities in the genetic control of both qualitative and quantitative traits among the four hybrid populations, with only small differences due to the different cultivated parents. However, larger differences were apparent between the populations involving ACC 1 and ACC 87.

Estimates of narrow sense heritability were high for many of the qualitatively inherited traits, indicating high additive genetic variance for those traits, and thus the capacity for genetic gain through selection. Transgressive segregation occurred for most of the quantitative traits in one or more of the four crosses, indicating the potential value of the wild germplasm in broadening the phenotypic range available to plant breeders. Several phenotypic and genotypic interrelations found between many of the wild traits among the four crosses. In particular, there were several significant genetic correlations among quantitative traits, indicating that selection for one of the traits should result in genetic advance in the other.

The study confirmed earlier research that Australian accessions of the wild mungbean can be considered part of the primary gene pool of the cultivated mungbean. Consequently, the wild accessions provide an additional source of triats potentially useful for mungbean improvement. The study also established that traits of possible commercial interest, perenniality and powdery mildew resistance, were qualitatively inherited and thus should be readily transferrable into cultivated varieties. While the study failied to identify the presence of a LJ trait, it suggested that the wild germplasm could be a useful source of lateness genes for breeding vegetatively vigorous forage or cover crop varieties of mungbean.

Item ID:	31508
Item Type:	Thesis (Masters (Research))
Keywords:	crop legumes; genetics; physiology; plant breeding; wild germplasm; wild mungbean
Copyright Information:	Copyright © 2011 Nguyen Dat Thuan
Date Deposited:	30 Apr 2014 07:02
FoR Codes:	07 AGRICULTURAL AND VETERINARY SCIENCES > 0703 Crop and Pasture Production > 070305 Crop and Pasture Improvement (Selection and Breeding) @ 100%
SEO Codes:	82 PLANT PRODUCTION AND PLANT PRIMARY PRODUCTS > 8204 Summer Grains and Oilseeds > 820499 Summer Grains and Oilseeds not elsewhere classified @ 100%
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