Genotype and genotype x environment interaction of some rice grain qualities in Tanzania

1. Genotype and genotype x environment interaction of some rice grain qualities in Tanzania Nkori J.M. Kibanda1 and Ashura Luzi-Kihupi2 1 Rice Breeder 2 ECARRN Coordinator

2. Genetic and Genotype x environment interaction cont.. Introduction • Genotype x environmental interaction • Is important in plant breeding programs • When is large, testing in several (stratified) environments becomes necessary • to optimize testing environments

3. Introduction cont.. • adequately measure genetic value of a cultivar • Reports on the effect of genotype, genotype x environment interaction on rice grain qualities are available (Resurrecion, 1977, Mackill et al.1996, Unevehr et al, 1992)

4. Objectives This study had the following objectives: - • Overall objective • Investigate the response of newly breeding rice genotypes and their interaction on the performance grain quality attributes under varying environments

5. Specific objectives Specific objectives • To assess the contribution and the relative magnitudes of rice variety and variety x environment interaction on physical and biochemical traits under upland and irrigated ecosystems • To estimate and assess correlations and genetic parameters of physical and biochemical grain quality attributes and determine their relative importance on rice improvement under upland and irrigated cultures

6. Materials and Methodology • Location: TAC (Ifakara) and SUA (Morogoro) • Soil and weather data were determined • Rice genotypes • Collected from ARI KATRIN and SUA • Selected based on yield potential • Composed of conventional and mutants

7. Materials and Methodology cont.. • Genotypes: SSD1, SSD3, SSD5, M15A,Line85, Line88, TXD275, TXD220, TXD306 and Supa (control • Design: RCBD; • Three replications with 2m x 4m • Seeding: 2-3 seeds/hill at 20cm x 20cm • Agronomic practices

8. Materials and Methodology cont.. • Data recorded: • Grain size and shape, opacity - (Jennings et al. 1979, IRRI 1988) • AC - Modified simplified assay procedure (Jliano et al. 1981) • GC – (Campagn et al. 1973)

9. Statistical analysis • Statistical Analysis • Analysis of variance (ANOVA) • Single site and combined analysis – SAS software • Estimates of variances of G, E, G x E interactions (AlJibouri et al. 1958) • Estimates of Genetic Coefficient of Variation (Burton 1952)

10. Statistical analysis cont.. • Estimates of Heritability in the broad sense (Hanson et al. 1956) • Estimates of Genetic Advance at 5% intensity (Johnson et al. 1955) • Estimates of Phenotypic and genotypic correlation

11. Table 1a: Performance of rice lines/variety on physical analysis at SUA

12. Table 1b: Performance of rice lines/variety on biochemical analysis at SUA

13. Table 2a: Performance of rice lines/variety on physical analysis at TAC

14. Table 2b: Performance of rice varieties/lines on biochemical traits at TAC

15. Table 3a: Performance of rice lines/variety on physical traits combined in two locations (SUA &TAC)

16. Table 3b: Performance of rice lines/variety on biochemical traits combined in two locations (SUA &TAC)

17. Results and discussion cont.. • Genotypes were significant in all the traits except for grain shape in all the locations an when data were pooled • Performance of genotypes on the traits varied across environments • Grains ranged from very long to medium, slender to intermediate grain shape with small opacity

18. Table 4: Mean squares from combined analysis of variance (ANOVA) for different physical and biochemical characters/traits at SUA and TAC

19. Results and discussion cont.. • Location and genotype mean squares were significant on chalkiness, AC, GC and GT • Genotype x Environment interactions were significant on AC, GC and AC

20. Table 5: Genotypic (top) and phenotypic correlations of rice grain qualities from 10 rice genotypes combined from SUA & TAC

21. Results and discussion cont.. • Significant genotypic and phenotypic correlations were positive between AC with GC suggesting that selection for GC would simultaneously improve AC, but with significant negative correlation with GT • Similar result between AC and GC have been reported (Juliano and Villareal, 1993)

22. Table 6: Table Variance components of grain qualities of 10 rice genotypes at SUA and TAC

23. Results and discussion cont.. • High genetic variance were on chalkiness, GC and AC • High heritability on GL, AC and GC • High genetic advance on GC

24. Conclusion • Grain qualities varied among genotypes and in varying environments • Most lines tested meet most of the market and consumers’ preferences in Tanzania (Long to medium) grain size with slender to intermediate shape, intermediate AC, intermediate GT and soft GC • GC had high heritability and genetic advance and had significant positive phenotypic and genotypic correlations with GL and AC suggesting that GC can be used as a reliable selection criterion for indirect improvement of AC in early generations in specific environments