| Autor: |
Jorge de Oliveira, Eder, Santos de Oliveira, Saulo Alves, Vilas Boas, Sandielle Araújo, Hohenfeld, Camila Santiago, da Silva Santos, Vanderlei |
| Zdroj: |
Euphytica; Aug2017, Vol. 213 Issue 8, p1-13, 13p, 5 Charts |
| Abstrakt: |
Cassava root rot disease (CRRD) severely affects productivity in several countries. The objective of this study was to estimate genetic parameters and to identify multiple resistance sources against pathogens associated with CRRD. The symptoms caused by Fusarium spp., Phytophthora spp., and Botryosphaeriaceae species in peel and pulp from the roots were evaluated in 277 accessions using a whole tuberous root inoculation method. The resistance data were obtained by REML/BLUP (restricted maximum likelihood/best linear unbiased predictor). The classic selection index (CI), multiplicative (MI), and sum of ranks (SRI) were used to identify the accessions with multiple resistance. For all pathogens, the environmental variance (σe2 ) was the most important component. Individual heritability hg2 was of low magnitude for resistance to most pathogens (0.16 ± 0.02—peel and 0.31 ± 0.03—pulp for Fusarium spp.; 0.26 ± 0.03—peel and 0.30 ± 0.03—pulp for Phytophthora spp.; and 0.28 ± 0.03—peel and 0.27 ± 0.03—pulp for Botryosphaereacea species). The distribution of CRRD symptoms indicated the presence of quantitative inheritance. The direct selection of the 15 more resistant accessions based on the genotypic predicted values result in high reductions of disease ([50%). However, there was a low matching rate of the most resistant accessions for each pathogen and the different parts of the tuberous roots (peel and pulp). The CI and MI were the most promising compared to the SRI to ensure high and balanced resistance for each pathogen. Understanding the genetic basis of resistance to CRRD and the identification of sources with multiple resistance may be useful in various management strategies to control the disease. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
