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According to our previous investigations, resistance to Phytophthora capsici in Capsicum annuum genotypes, 'Line 29', 'P1201232', 'P1201234' and Serrano Criollo de Morelos 334 ('SCM334'), seems to be controlled by three genes. In order to determine the genic relationships between these four sources of resistance, three experiments were conducted which included the four genotypes, their F1s, F2s, F3s and BC1 generations together with the susceptible pepper genotype 'Morrón INIA 224'. Inoculations were made, when plants had 46 leaves, by irrigating the culture substrate with a zoospore suspension of P. capsici isolate 'Bl'. Though the four genotypes showed percentages of resistance close to a 100%, none of them actually reached this level in the three experiments. 'SCM334' was the most resistant genotype, transmitting a high level of resistance to its F1, F2 and BC1 generations. 'Line 29' was more resistant than 'P1201232' and 'P1201234'. However, the F1, F2 and BC1 generations of these three lines showed similar degrees of resistance. The four genotypes seem to have one of the three genes postulated for their resistance in common. All genes displayed a similar level of resistance, except the specific genes of 'SCM334', the effect of which was slightly higher. Several working procedures are suggested for breeding programmes. [ABSTRACT FROM AUTHOR]

In order to establish a genetic model of the resistance to Phytophthora capsici in Capsicum annuum genotype 'SCM-334', two experiments were conducted which included 'SCM-334', as well as, the susceptible line 'Morrón INIA 224' and their F1, F2, F3 and BC1 generations. We also tried to introgress a recessive gene, hypothetically responsible for resistance to P. capsici, from 'SCM-334' into 'Morrón INIA 224'. Inoculations were made, when plants had 4--6 leaves, by irrigating the culture substrate with a zoospore suspension of P. capsici isolate 'BI'. The χ² test was applied to segregating generations to determine how many genes were involved in resistance. The hypothesis which explained the obtained segregations best, although not completely, was one that assumes 3 genes in 'SCM-334', with at least 3 alleles in the heterozygous condition or 4 at any position, present in any genotype in order to be resistant. The influence of the isolate's aggressiveness and the inoculation method on the results are discussed. [ABSTRACT FROM AUTHOR]