Print version ISSN 0006-8705
SERA, Gustavo Hiroshi et al. Selection for resistance to rust in progenies of coffee cultivars IPR 99 and IPR 107. Bragantia [online]. 2010, vol.69, n.3, pp. 547-554. ISSN 0006-8705. http://dx.doi.org/10.1590/S0006-87052010000300005.
All plants of the coffee cultivars IPR 99 ("Sarchimor") and IPR 107 ('IAPAR 59' x 'Mundo Novo IAC 376-4') were resistant to rust (Hemileia vastatrix) in the past. Currently, susceptible plants were observed in the two cultivars due to the breakdown of resistance by new rust races. The aims of this study were: a) to identify coffee (Coffea arabica L.) progenies of the two cultivars with resistance to rust; b) to identify progenies with incomplete resistance; c) to investigate the efficiency of test-crosses for selection from these cultivars. Evaluation for field resistance was carried out in adult plants subjected to natural infection by the local leaf rust population at IAPAR. Twenty-three test-crosses with F3 progenies of 'IPR 107' and five with F4 progenies of 'IPR 99' were evaluated. Moreover, 11 F4 progenies of 'IPR 107' and five F5 progenies of 'IPR 99' derived from self pollinations were evaluated. Several progenies of the IPR 99 and 107 cultivars presented high frequency of resistant plants and thus should carry additional SH genes not defeated by specific rust races found at IAPAR. However, susceptible progenies of 'IPR 99' and 'IPR 107' presented incomplete resistance to the local race population. Test-crosses were efficient for selecting coffee progenies more resistant to rust.
Keywords : Coffea; durable resistance; Hemileia vastatrix; SH genes; test-cross.