Simone Alves Silva

Genetic Basis of Stay-Green Trait in Bread Wheat

ABSTRACT The stay-green trait is responsible for the preservation of green coloration in the stem and leaf, during physiological maturity. It has also been shown to play an important role in the increase of grain size. The knowledge of the inheritance of this trait can constitute valuable information to plant breeders in the developing new wheat (Triti-cum aestivum L.) varieties. This study was conducted in two environments, during the years of 1997 and 1998, to verify the genetic basis of the stay-green trait among crosses of four different genotypes in the field and three in the greenhouse. The analysis was based on three fixed (P1, P2 and F1) and three segregating (F2, BC1F1 and BC2F1) generations. Means and variances were computed for every generation for each cross and the nature of the gene and its effects were estimated. Change in stem color was used as the criterion for the stay-green trait in three phases of development in wheat, based on scores obtained from visual analysis, on a scale of 1 to 10. The results presented in the 2nd observation phase, suggest that the stay-green trait is controlled by only one gene with two alleles and gene activity with high predominance of additive effects and to a lesser degree, a partial dominance for stay green.

Enraizamento in vitro e aclimatização de genótipos de jenipapeiro (Genipa americana L.)

The rhizogenesis is considered a critical stage, since it determines the plant survival during the acclimatization. Among the determinative factors in the induction and the formation of in vitro roots, is distinguished the genotype and the auxin. The objective of the work was to evaluate the effect of different concentrations of acid 4-indol-3-butirico (IBA) in the in vitro rooting in genotype of Genipa americana L; as well as the process of acclimatization of the plant using different substrate. For the in vitro rooting stage, shoots of 2.0 cm long, proceeding from the culture medium with 6-benzilaminopurina (BAP) in concentrations of 2,22; 8,87; 17,74 and 26,76 µM plus the witness with absence of the BAP, were inoculated in medium MS supplemented with IBA (4.9; 9.8 e 14.7 µM) plus the witness with IBA absence. To the acclimatization process it was used as supporting material washed sand, Plantmax® HT and Ecoterra®. The variables analyzed were: percentage of rooting, number of adventitious roots, and length of the largest root, percentage of survival and height of the plant in the acclimatization phase. The results showed that IBA at 9.8 mM induced greater rooting percentage. The substrate Ecoterra® influenced significantly in the quality of root system and quality of the aerial part.

Divergência genética em feijão-caupi

This work aimed to evaluate the genetic divergence among cowpea genotypes, for selection of most divergent genotypes and of highest yield potential as parents in crossings as well as for future recommendation of cultivars in the reconcave region in Bahia, Brazil. The experiment was carried out Agronomy School of Universidade Federal da Bahia, Cruz das Almas, State of Bahia, using twenty two erect cowpea and twenty semi-erect cowpea genotypes, in a randomized design, with four replications. The following characters were analyzed: plant height, pod length, pod weight, grain weight for pod, number of grains for pod, weight of hundred grains, grain index, pod yield and grain yield. The genetic divergence was obtained by means of the Mahalanobis generalized distance. New genetic combinations can appear in the crossings among the TE97-309G-1, TE97-367G-3, TE97-367G-11 climbing genotype and TE97-430G-12 and TE97-321G-4 and TE97-404-1E-1 semi-erect genotypes. The selection of the climbing genotypes TE93-244-23F-1, TE97-299G-10 and BR 17-Gurgueia and the TE97-321G-4, TE97-406-2E, TE96-282-22G and EV x 91-2E-1 semi-erect genotypes demonstrated superiority for grain yield. Pod length, weight and yield characters are ones that contribute most to the genetic divergence.

Divergência genética entre cinco cultivares de mamoneira

The objective of this work was to evaluate the genetic divergence between castor bean (Ricinus communis L.) cultivars, from adaptative traits, yield components and cultivars productivity. The experiment in a randomized blocks design with five treatments and five replications was carried out in a Xanthic Hapludox in Cruz das Almas, BA, Brazil. Data were submitted to the variance analysis and the average values had been commanded according to Scott-Knott test (a = 0.05). Based on multivariate analysis, the genetic divergence was determined using cluster analysis and principal components analysis. Tree groups were formed, and the one which comprised the cultivate more divergent, Mirante 10, is not recommended for hybridization due to its low performance. Promising combinations are those ones found between Sipeal 28 x BRS 188 Paraguacu, Sipeal 28 x BRS 149 Nordestina, EBDA MPA 17 x BRS 188 Paraguacu and EBDA MPA 17 x BRS 149 Nordestina, due to the dissimilarity and the best average performance of these genotypes.

Adaptabilidade e estabilidade fenotípica em genótipos de feijão de cor (Phaseolus vulgaris L.) em três ambientes distintos

In the biennium 1996/97, twenty-one genotypes of colored bean were evaluated, in three environments, to identify and estimate adaptability parameters and phenotypic stability for grains yield. The experimental design was randomized blocks with three replications per treatment. The genotypes revealed highly significant differences among them, in all evaluated environments. In the analysis of joint variance, the genotype effects, environment and the interaction genotype x environments were highly significant, showing differences among genotypes x environment, and the existence of a differentiated behavior among genotypes according to enviromental variation. Average grain yields varied from 1321kg.ha-1 to 801kg.ha-1, with on overall average of 1081kg.ha-1. Most of the genotypes evidenced high phenotypic stability, specially LP 93-15, LP 93,2, LP 93-38 and Ruda, which showed superior average yield compared to the overall yield average, general adaptability and predicted behavior in all the studied enviroments. Among the genotypes with grain yield below the overall average AN 9022180, LM 93204319, LR 91155315, PF 9029975, PF 9029984 and TB 94-05 presented general adaptability and high phenotipic stability in the environments evaluated.

Caracteres relacionados com a resistência ao acamamento em trigo comum

Grain yield is affected by plant lodging, and this is a serious problem mainly for tall wheat cultivars. A field trial was conducted during 1999 growing season to investigate the variability for some morphological traits associated to lodging resistance in 14 wheat genotypes. It was found variability for all traits evaluated. Values of lodging resistance coefficient, plant height, length of peduncle and culm index were highly correlated with lodging resistance. These traits can be recommended for lodging resistance indirect selection. Among genotypes evaluated, line TB 951 showed the best performance for all traits related to lodging resistance. So, that line can be indicated as an excellent lodging resistance source in bread wheat.

Composição de subunidades de gluteninas de alto peso molecular (HMW) em trigos portadores do caráter "stay-green"

The objective of this work was evaluate stay-green trait behavior in wheat plants as bread-making quality through eletrophoretic standars of this proteins and phenotypic Pearson correlation among adaptatives caracters as head-date and plant stature, coloration (stay-green) and proteic scores. The experiment was driven in field conditions and laboratory in the years of 1999 and 2000. The trait stay-green expressed in the appraised genotypes showed high correlation with the proteic scores obtained through the eletrophoretic analysis of this subunits could be suggested as parameter to select superior plants for glutenins and consequently with larger bread-making quality.