β-decay of odd-A Ti57 and V59

The β-decay of odd-A, neutron-rich Ti57 and V59 are studied. More precise β-decay half-lives of 98±5 and 97±2 ms are deduced for Ti57 and V59, respectively. In addition, β-delayed γ-ray spectroscopy is used to deduce β-decay branching ratios and establish the low-energy-level structures of the daughter nuclides. The new data for levels in V57 and Cr59 are compared with the results of shell-model calculations completed in the full pf model space. Both V57 and Cr59 show evidence of modest oblate deformation near the ground state

Development of new shell structure in pf-shell nuclei

β-delayed γ-ray measurements have been part of an experimental program at the NSCL to understand the role of the πf7/2 - νf5/2 proton-neutron monopole interaction in neutron-rich pf-shell nuclei above 48Ca. Central to this study has been an attempt to observe the development of new shell structure at N 32, 34 through the systematic observation of E(2+1 ) as a function of neutron number. Additionally, the ground state spin and parity of odd-odd and odd-A nuclei were interpreted in an extreme single-particle model to follow the monopole migration of the νf5/2 as protons are removed from the πf7/2state

Beta-delayed γ-ray studies of φf7/2 - νpf shell nuclei

We have utilized the selective process of β decay to populate low-energy excited states in the neutron-rich 22Ti, 23V, 24Cr, and 25Mn nuclei. The goal was to systematically track the monopole shift of the νf5/2 single-particle level with increased occupancy of the φf7/2 orbital.The β-decay properties of the parent nuclides, along with the low-energy structure of the daughters, are presented and compared with the results of shell model calculations employing the GXPF1 interaction

Genotype × environment interaction for the agronomic performance of high β-carotene sweetpotato

Sweetpotato (Ipomoea batatas L.) is an important tuber vegetable for human health worldwide owing to its nutritional value and productivity. Consumption of orange-fleshed sweetpotato is beneficial to combat vitamin A deficiency in the world, including Brazil, as these tubers are rich in beta-carotene, a precursor of vitamin A. The genotype x environment interaction is one of the greatest challenges in plant breeding, specifically in the selection and approval of cultivars. In this context, adaptability and stability analyses are warranted to evaluate the performance of various genotypes in terms of general or specific adaptations to certain environments and to identify genotypes responsive to environmental variations. Thus, the objective of this study was to evaluate the genotype x environment interaction as well as to estimate the adaptability and stability of sweetpotato genotypes for identifying and selecting promising candidates for breeding. The experiments were performed in four environments: Vera Cruz in Sao Paulo, Selviria in Mato Grosso do Sul, and one organic and another intercropped production system in Sete Barras in Sao Paulo. A randomized block design with two replicates was adopted. A total of 265 genotypes were tested, and the orange-fleshed sweetpotato cultivar 'Beauregard' was used as the control. The additive main effects and multiplicative interaction model was used to study environmental stratification, adaptability, and stability. The genotype x environment interaction was evident in all environments. The genotypes CERAT21-13 (marketable root yield, 22.30 t ha(-1) in the four environments), CERAT29-26 (27.74 t ha(-1)), and CERAT52-22 (20.24 t ha(-1)) were the most adapted in general to the four environments. CERAT25-23, CERAT29-23, and CERAT29-26 were the most adapted to the environment in Vera Cruz; CERAT29-26, CERAT34-14, and CERAT56-32 to the environment in Selviria; and CERAT31-10, CERAT35-19, and CERAT52-22 to the two environments in Sete Barras

Prediction of genetic gains in sweet potato genotypes by polycross

Sweet potato crops present a wide genetic diversity, but genetic parameters of populations should be estimated in breeding programs, mainly when the selection is focused on multiple traits. Thus, the objective of this study was to estimate genetic parameters and select clones via a selection index in a sweet potato population obtained from uncontrolled crosses. The experiment was carried out in Ilha Solteira, Sao Paulo, Brazil, from June to November 2020, to evaluate 144 clones and three controls, totaling 147 treatments. A randomized block design was used, with two replications and three plants per plot. The data were analyzed through mixed modeling (REML/BLUP), and the selection index proposed by Mulamba & Mock was applied using a selection pressure of 17.3% for the selection of superior clones. The direct selection enabled a higher prediction of gains for each trait, but the joint analysis maximized the selection gains for all traits of interest. Clones 38, 63, 79, 77, and 5 are recommended, among the selected clones, for further stages of sweet potato breeding focused on improving traits for production and table consumption

Genetic parameters and gain from selection in sweet potato genotypes with high beta-carotene content

Estimating genetic parameters is an essential procedure to define strategies for breeding and selection of higher yielding genotypes. The use of a selection index can assist in decision making by combining the high yield trait with other desirable traits. The objective of this study was to verify the possibility of gains from selection in a sweet potato population to select potentially promising genotypes. The experiment was conducted in a randomized block design, with three plants per plot and two replications, consisting of 255 sweet potato genotypes and a commercial cultivar (256 treatments). The data were analyzed through REML/BLUP. Genetic gains were evaluated using selection indexes based on the rank sun. The plant population tested showed high genetic variability; 81.25% of the traits had genotypic coefficients of variation above 20%, which indicates conditions favorable to selection with considerable genetic advances. CERAT31-01, CERAT21-02, and CERAT51-30 can be recommended as the most promising genotypes

Genetic divergence of sweet potato genotypes based on morpho-agronomic traits

Sweet potato is a vegetable of great importance in human consumption, due to its high nutritional value. It presents high phenotypic variation, with different forms of roots, leaves and vines. Given the above, we aimed to study the genetic divergence of sweet potato genotypes based on morpho-agronomic traits. The experiment was conducted in an experimental area of Unesp, Ilha Solteira Campus, located in Selvíria-MS. The experimental design used was randomized blocks with two replicates, including 200 genotypes and ‘Beauregard’ as a biofortified control. Shoot morphological traits of the genotypes were evaluated at 110 days and root morphological traits were evaluated at 127 days after planting. We used the obtained data to perform descriptive analysis, in percentage of phenotypic classes. In order to study genetic divergence, multivariate analysis was performed, grouping was done using Tocher’s and Ward’s methods. We also analyzed relative contribution of each trait for genetic divergence. Statistical analyzes were performed using Genes software and SAS. Wide genetic variability could be verified in the population studied in this experiment, being possible to obtain genetic gains in recombination between genotypes. Grouping using Tocher’s method was more effective for discriminating dissimilarity between genotypes. The low relative importance of leaf size, internode diameter and secondary peel color makes further evaluation of these traits unnecessary, reducing labor costs, cost and execution time