Genetic Analysis and Improvement of hot perrper for yield, yield related traits and resistance to potato virus and Ethiopian pepper mottle virus.

Hot pepper (Capsicum annuum L. var. annuum) is an important spice and vegetable crop in Ethiopia.However, lack of genetic information on yield, yield related traits and genetic tolerance to infections by potyviruses and their aphid vectors has constrained the improvement of the crop in the country.This study was, therefore, aimed at estimating hererosis, combining abiligy, genetic components and inheritance of yield, yield related traits andthe extent of genetic tolerance of hot pepper to potyvirus infections and their aphid vectors.the study was carried out in three field experiments from 2003 to 2007 at three representative hot pepper growing sites in Ethiopia, namely, Bako, Hawasa and Melkasa.Three Ethiopian evolved cultivars and nine Asian evolved pure-line genotypes of the crop were used to produce experimental entries in three cycles of crossings and selfing.The first cycle (December 2003 to May 2004) was meant to produce 66 F1 and 12 parental selfs in a half-diallel crossing (fixed effect model) for the first experiment (October 2004 to Juen 2005).The two second cycles (January to June 2005)were meant to produce progeny generations (F1,F2, B1 and B2) of selected crosses and fresh seeds of their parental genrations (P1 and P2) for the second experimant (August 2005 to March 2006), one preliminary trial (January to June 2006) and the third experiment (January to June 2007).Planting the experimental entries for each of the three experimnets was done in a randomized complete block design.Data were recorded on plant, fruit and disease incidence traits as well as on virus vectors.Half-diallel and generation man analysis were done for the recorded data.Maximum heterosis over midparent and better-parent, and economic superiority of a hybrid over the standard check were obtained, respectively for dry fruit yield per plant (163.8% and 161.8% and 92.1%), number of fruits per plant (104.4%, 79.6% and136.4%) and days to maturity (-29.8%,-31.5% and 23.6%). Crosses between Asian and Ethiopian evolved genotypes produced more proportions of F1 hybrids with the highest specific combining ability effects for dry fruit yield, the number of fruit per plant, pericarp thickness and days to maturity.In further analysis of the data of the first experiment to identify components of vairtion, total genetic variability was revealed for 7 traits among the 78 entries with excess of over-dominance genes.There unequal distributions of dominant genes with positive and negative effects among the parents.Significant variabiity in environmental sensitivity among the 78 experimental entries for some traits was also revealed along with high heritability. There is a possibiligy to pyramiding favorable alleles for the fruit traits with polygneic inheritance.Similarly, there is a possibility of minimizing SSE and developing PVY and EPMV tolerant varieties of hot pepper through crossing and recurrent selection procedures in diverse genotypes of the crop.avoiding early infections by excluding aphid vectors at seedling stages of the crop plants may also minimze crop losses due to potyvirus infections.