Full text in pdf format

Selection of local lowland rice cultivars based on multivariate genetic divergence

Paulo Hideo Nakano Rangel^I; Cosme Damião Cruz^II; Roland Vencovsky^III; Reinaldo de Paula Ferreira^I

^IEMBRAPA/Centro Nacional de Pesquisa de Arroz e Feijão (CNPAG), Caixa Postal 179, 74000 Goiânia, GO, Brasil. Send correspondence to P.H.N.R.
^IIDepartamento de Biologia Geral, Universidade Federal de Viçosa, 36570 Viçosa, MG, Brasil
^IIIDepartamento de Genética, ESALQ/USP, Caixa Postal 83, 13400 Piracicaba, SP, Brasil

ABSTRACT

Seventy two local rice cultivars, adapted to lowland conditions, were evaluated, considering ten traits of agronomic importance. Their genetic divergence was evaluated through multivariate procedures, to orient the constitution of base populations for breeding purposes.
The clustering procedure proposed by Tocher was applied to Mahalanobis generalized distances; all cultivars could then be organized into four groups.
Special emphasis was given to the divergence within a group of 13 distinct cultivars identified as superior in relation to grain yield.
Measures of divergence permitted the recognition of two special groups within the set of 13, namely: group 1, with cultivars 49, 6, 35, 34, 38 and 13; group 2, with cultivars 59, 41, 37, 23, 3, 21 and 30. These groups seemed to be adequate for intercrossing in a factorial mating design (group 1 x group 2). Alternatively, cultivars of these groups could be used for intercrossings with introduced elite lines, already improved in terms of plant architecture.
Divergence was also detected among cultivars with the same denomination (Matão and Chorinho), but collected at different locations. It was inferred that these materials could have undergone a process of genetic divergence due to contrasting environmental conditions, maintained through decades of cultivation. The divergence detected in these cultivars with identical denomination was more pronounced for days to flowering than for other traits.

Keywords: Selection; Rice; Multivariate genetic divergence.

REFERENCES

Geraldi, I.O. and Miranda-Filho, J.B. (1988). Adapted models for the analysis of combining ability of varieties in partial diallel crosses. Brazil.1. Genet. 11: 419-430.

Kaw, RN. (1988). Combining ability for low temperature germinability in rice. Genet. Agr. 42: 43-49. Lopes, A.M. (1984). Análise genética dos componentes de produção num dialelo entre seis cultivares de arroz (Oryza saliva L.) em dois regimes hídricos. Doctoral Thesis, Universidade Federal de Viçosa, MG.

Mahalanobis, P.C. (1936). On the generalized distance in statistics. Proc. Natl. Inst. Sci. 2: 49-55.

Maurya, D.M. and Singh, D.P. (1977a). Genetic divergence in rice. Indian J. Genet. Plant. Breed. 37: 395-402.

Maurya, D.M. and Singh, D.P. (1977b). Combining ability in rice for yield and fitness. Indian J. Agric. Sci. 47: 65-70.

Miranda-Filho, J.B. and Geraldi, I.O. (1984). An adapted model for the analysis of partial diallel crosses. Brazil. J. Genet. 7: 677-688.

Mohanty, H.K. and Mohapatra, K.C. (1973). Diallel analysis of yield and its components in rice. Indian J. Genet. Plant Breed. 41: 179-185.

Ram. J. and Panwar, D.V.S. (1970). Intraspecific divergence in rice. Indian J. Genet. Plant Breed. 30: 1-10.

Rao, R.C. (1952). Advanced Statistical Methods in Biometric Research. John Wiley and Sons. New York, PP- 390.

Rao, A.V., Prasad, A.S.R., Sai, Krishna, T., Seshu, D.V. and Srinivasan, T.E. (1981). Genetic divergence among some brown planthopper resistance rice varieties. Indian J. Genet. Plant Breed. 41: 179-185.

Scott, A.J. and Knott, MA. (1974). A cluster analysis method for grouping means in the analysis of variance. Biometrics 30: 507-512.

Shrivastava, M.N. and Seshu, D.V. (1983). Combining ability for yield and associated characters in rice. Crop Sci. 23: 741-744.

Singh, D.P. and Nanda, J.S. (1976). Combining ability and heritability in rice. Indian J. Genet. Plant Breed. 36: 10-15.

Singh, R.S. (1977). Combining ability for grain yield and panicle characters in rice. Indian J. Genet. Plant Breed. 37: 384-387.

Singh, R.K. and Chaudhary, B.D. (1979). Biometrical Methods in Quantitative Genetic Analysis. Kalyani Publishers, pp. 304.

Singh, V.P., Swaminathan, M.S., Meiira, R.B. and Siddiq, E.A. (1979). Divergence among dwarfs of cultivated rice. Indian J. Genet. Plant Breed. 39: 315-322.

Vencovsky, R. (1987). Herança Quantitativa. In: Melhoramento e Produção de Milho no Brasil (Paterniani, E. e Viegas, G.P., eds.). Edição da Fundação Cargill, 2^a ed., Vol. 1, Campinas, pp. 135-214.