Micheli Thaise Della Flora Possobom

Comparison among direct, indirect and index selections on agronomic traits and nutritional quality traits in common bean.

BACKGROUND Selection indices are linear combinations that allow the selection of several characters simultaneously. The objective of this study was to verify the efficiency of direct selection, indirect selection and selection indices in the identification of higher inbred common bean lines for grain yield, morphological, phenological and nutritional traits. RESULTS There is genetic variability for grain yield, lodging, general adaptation note, cycle, insertion of the first pod, calcium and iron concentrations in the seeds. Moderate phenotypic correlation coefficients were observed between grain yield and general adaptation note (r = -0.57) and cycle (r = -0.57). When direct selection was performed for grain yield, the insertion of the first pod, calcium and iron concentrations showed negative indirect selection gains. The classic index showed that the distribution of gains has become more balanced: grain yield (39.05%), calcium (8.29%) and iron concentration (1.64%). CONCLUSION Direct selection and indirect selection are not efficient in the simultaneous selection of agronomic traits and nutritional quality in common bean. The classical, base and multiplicative indexes provide responses of gain balanced among traits and superior genetic progress in the selection of inbred common bean lines, and have a high coincidence between the lines selected.

Seleção de linhagens de feijão com alto desempenho agronômico e elevadas concentrações de cálcio e ferro

The objective of this work was to evaluate the genetic variability of common bean lines for cycle, weight of 100 grains, grain yield, cooking time, and grain calcium and iron concentrations. Twenty-four common bean lines were evaluated in two crop cycles (2010 and 2011). The ¯Z index was used for the selection of superior lines for most of the traits. The DF 06-19, DF 06-03, DF 06-17, DF 06-20, DF 06-11, DF 06-14, DF 06-01, DF 06-08, DF 06-22, and DF 06-04 lines showed high grain yield. All lines were of semi-early cycle and of fast cooking. The DF 06-08 and DF 06-23 lines showed high calcium concentration in grains (>1.4 g kg-1 dry matter - DM), and the DF 06-09, DF 06-03, DF 06-04, and DF 06-06 lines presented high iron concentration in grains (>0.95 g kg-1 DM) in the two crop cycles. The DF 06-09 and DF 06-03 carioca lines present high agronomic performance and high iron concentration in grains. The DF 06-17 and DF 06-08 black lines present high agronomic performance and high calcium concentration in grains. The selection of the DF 06-09, DF 06-03, DF 06-17, and DF 06-08 lines is recommended.

Genetic control of potassium content of common bean seeds

The objective of this work was to investigate possible maternal effects on potassium content of common bean seeds, as well as to estimate the heritability and selection gains in early hybrid generations for this character and to evaluate the efficiency of genetic selection to improve the nutritional quality of common bean (Phaseolus vulgaris). Crosses with four cultivars from the Mesoamerican gene pool yielded the reciprocal F1 and F2 generations and the backcrossed populations (BCP1 and BCP2). The potassium content of the progenies was measured via nitric‑perchloric digestion and flame photometry. The potassium content in the tested progenies varied from 6.0 to 14.9 g kg-1 dry matter, and no significant maternal effect was observed. The narrow-sense heritability ranged from low (33.26%) to intermediate (43.05%). Partial dominance was observed for low potassium content in the seeds. No increase in potassium content was obtained through selection. Breeding common bean plants for increasing potassium content in seeds may be difficult because the local environment strongly influences the character.

Methods of selecting common bean lines having high yield, early cycle and erect growth

Selection for grain yield, combined with phenological and morphological characteristics of agricultural interest, represents technological advances in the common bean. The objectives of this work were to estimate genetic parameters and the efficiency of both the Pedigree and Single-Seed Descent (SSD) methods for progression segregating populations in order to obtain common bean lines superior in grain yield, precocity and plant architecture. To do this, 136 inbred lines obtained using the Pedigree method, and 136 inbred lines obtained by SSD method were evaluated in a 17 x 17 simple lattice design, integrating the 272 inbred lines in the F 7 generation and 17 cultivars as control. Estimates of moderate narrow sense heritability were obtained for grain yield, lodging and insertion of the first pod. The cycle and general adaptation note showed low heritability for the F 7 generation. The Pedigree method allows obtaining a greater number of lines of high grain yield, early cycle and a lower general adaptation note (best adaptability). Selection using the Single-Seed Descent method allows the identification of a larger number of lines with lower notes for lodging and higher insertion of the first pod.

Inheritance pattern of zinc (Zn) concentration in Middle American and Andean common bean (Phaseolus vulgaris L.) seeds

The development of common bean cultivars biofortified for zinc meets the global demand for food which may help minimize nutritional deficiencies. The objectives of this research were to investigate the distribution of zinc in the four different Middle American and Andean common bean (Phaseolus vulgaris) seeds, to estimate the genetic parameters for zinc concentration in seeds, and to select recombinants biofortified for zinc. Thus, controlled crossings were carried out between the Middle American lines CNFP 10104 and CHC 01-175, and the Andean cultivars Cal 96 and Hooter. Seeds from F1, F1 reciprocal, F2, F2 reciprocal, and backcross (BC11 and BC12) generations were obtained. Parents and segregating generations were evaluated in two field experiments performed in Brazil. In the parents evaluated, from 57.01 to 68.47% of zinc was accumulated in the seeds embryo. Zinc concentration in Middle American and Andean common bean seeds had no significant maternal effect. Zinc concentration in common bean seeds ranged from 11.59 to 49.84 mg kg -1 of DM in F2 generation, and showed a continuous distribution, which is characteristic of quantitative inheritance. Broad-sense heritability of zinc concentration in common bean seeds is of high magnitude (h 2 b= 67.21 to 90.03%) and from 17.32 to 27.80% of gain with selection is expected. From the tested hybrid combinations 112 recombinants with high zinc concentration in the seeds can be selected. Inheritance pattern of zinc concentration in Middle American and Andean common bean seeds is quantitative.

Selection of common bean lines for calcium use efficiency

The study of the calcium use efficiency in common bean is unprecedented. Therefore, the objectives of this work were to evaluate the genetic variability of common bean lines for plant growth and grain yield characters, the calcium accumulation in different plant tissues at low and high calcium availabilities, and to select common bean lines with high calcium use efficiency and responsive to the calcium application by different indices. Twelve common bean lines were supplied with a nutrient solution at low (1.10 mmol L-1) and high (3.85 mmol L-1) calcium concentration and were evaluated. The L 15 line reached the higher values of dry mass of shoot, number of pods and grains per plant, number of grains per pod and grain yield at the low calcium concentration. Calcium accumulation in tissues was, on average, higher in leaves, followed by stems, pods and grains. The L 175 and L 159 lines have higher calcium concentration in grains (> 1.1 g kg-1 MS), regardless of the calcium concentration supplied to plants. The L15 line is efficient in calcium use. The L 221 and L 159 lines are responsive to the calcium application in the rooting medium.