Roberto A Melo

Genetic similarity between coriander genotypes using ISSR markers

With the development of new cultivars, a precise genetic characterization is essential for improvement programs or for cultivar registration and protection. Molecular markers have been complementing the traditional morphological and agronomic characterization techniques because they are virtually unlimited, cover the whole genome and are not environmentally influenced. Genetic characterization constitutes the basis for studies involving estimates of genetic similarity. Therefore, the objective of the present study was to evaluate the genetic similarity between ten coriander genotypes (nine cultivars and one line) using ISSR markers. The cultivars used were: Americano, Asteca, Palmeira, Portugues, Santo, Superia, Tabocas, Tapacura, Verdao and the experimental line HTV-9299. The genetic similarity between the cultivars was estimated using 227 banded regions of ISSR molecular markers. The UBC 897 oligonucleotide generated the highest number of fragments (16), resulting in a higher polymorphism. The results indicate that the twenty-nine oligonucleotides chosen were satisfactory for detecting polymorphism. Based on the grouping analysis determined from the similarity data, there were two groups and two sub-groups. The calculated similarity for the genotypes varied from 52 to 75%. The lowest similarity was observed between Portugues and Verdao, at 52%. The highest similarity was found between Portugues and Palmeira, at 75%. The ISSR is efficient for identifying DNA polymorphism in coriander.

Adaptability and stability of pepper hybrids under conventional and organic production systems

Pepper is one of the main vegetable crops commercialized in Brazil and it is grown throughout the country. The objective of this study was to estimate genetic parameters and predict the genotypic values involved in agronomic traits of hybrid pepper in two different cropping systems in order to verify adaptability and genotypic stability. The experiment was carried out at the Experimental Station Luiz Jorge da Gama Wanderley from IPA, located in Vitoria de Santo Antao, Pernambuco State, Brazil, from October 2010 to March 2011. Seven hybrids were evaluated in two trials, the first in conventional farming system and the second in organic cultivation system. Randomized blocks were used with seven treatments, four replications and plots consisting of six plants. We evaluated the following fruit variables: total mass (MTF), total number (NTF), average length (CMF), average diameter (DMF), number of locules (NL) and average thickness of the pericarp (EP). Statistical analyzes and estimation of genetic parameters were based on mixed models of type REML/BLUP, using the statistical model and software SELEGEN 151. All traits showed good accuracy. The genotype average heritability (h2mg) was lower than 80% only for the trait NTF. Some characters had h2mg close to 100% such as CMF and DMF with 99.1% and 98.3%, respectively. The hybrids presenting a predicted genotypic effect higher than the average were: Atlantis, Maximos, Solario and Rubia R for NTF, Solario and Atlantis for MFT, Impacto, Maximos, Atlantis, Hebron and Rubia R to CMF, Solario and Enterprise for DMF, Solario, Impacto, Rubia R and Atlantis for NL and Solario and Enterprise for EP. Hybrids presenting the highest performance in the traits evaluated for each system were the same selected based on the joint analysis of the studied systems, showing stability and enabling their indication for organic and conventional cropping systems.