Divergência genética e capacidade de combinação em linhagens de pimentão (Capsicum annuum L.)

Abstract

In the genus Capsicum are inserted 32 species,predominantly originate from tropical and subtropical regions of America. Among the species of the genus is included Capsicum annuum L. containing the sweet peppers and some peppers. This study aimed to determine the genetic divergence using molecular marker of type ISSR and evaluate the ability general capacity (CGC) and specific capacity (CEC) of combination of linkages of sweet pepper. The experiment was conducted at the Department of Agronomy, Federal Rural University of Pernambuco (UFRPE), in Recife-PE, with latitude of 8 10'52''S and longitude 34 54'47''W between 20 July 2008 and 05 April 2009. Linkages were used HTV-1, HTV-8, HTV-9, HTV-10, HTV-11 and HTV-12, provided by the company Hortivale – Sementes do Vale LTDA, sown and whiting of around 20 days of sowing samples were collected for the first leaves to extract genomic DNA and the reactions of amplification with 21 primer’s of ISSR selected from a set produced by the University of Bristish Columbia, Vancouver, Canadá. After 30 days the seedlings were transplanted to pots with a capacity of five liters using coconut fiber as a substrate, fertirrigated daily with nutrient solution in greenhouse. During the flowering crosses were made in the morning is obeying the partial diallel among the six linkages resulted in fifteen experimental hybrids, where their fruits were harvested and seeds extracted manually. The six parents and the fifteen hybrids were evaluated in the greenhouse system similar to obtain the hybrids, using the experimental design of randomized blocks with four replications, where each experimental plot was composed of four pots with one plant each. The spacing between lines was 1.00 m and between plants in the same line of 0.5 m. The plants were conducted with only four stems and removed the lateral shoots up to the first fork and the flower thereof. The characteristics were observed and evaluated the following: total weight of fruit (PTF); total number of fruits (NTF), average weight of fruit (PMF); average fruit length (CMF); average fruit diameter (DMF); length/diameter ratio (RCD); average number of locules (NL); and average thickness of the pericarp (EP). Analysis of the ISSR the amplification of DNA fragments were 145, with an average of 6.9 per oligonucleotide fragments ranging from 300 to 1500 bp. Through the molecular data generated a dendrogram was, considering the average dissimilarity of 13.51%, which was the formation of three distinct groups. In the first group observed HTV-10, HTV-8, HTV-12 and HTV-11, already the second and third groups were formed by a genotype in each and they HTV-1 and HTV-9 respectively. The HTV-9 genotype was isolated from the others, presenting a dissimilarity of 20.31% with HTV-11, the most found among all genotypes. The small dissimilarity was found between HTV-8 and HTV-12 (4.92%) these materials are the most similar comparedwith other genotypes. In the study combining ability of the heritability obtained values between 48.4% and 91.4% for the features except the average number of locules has not submitted genetic variability. The ratios between CGC and CEC indicating that the actions of gene linkages studied favor the expression of additive genetic effects. With respect to the CGC, the linkage HTV-8 showed negative values for all characteristics evaluated, the linkages HTV-9 and HTV-10 showed highly positive for PTF. With respect to estimates of CEC, they were negative in all lines on the characteristics PTF, PMF, CMF and DMF. The hybrid HTV-8 x HTV-10 that stood out with higher PTF and PMF making promising potential as a hybrid business has, in addition to high CEC value for at least one of the parents with high value of GCC. The results obtained with molecular data showed some inconsistencies when compared to combinatorial analysis showing low accuracy, these materials, in the indication of possible superior hybrid combinations.