Potential for increasing the zinc content in common bean using genetic improvement

Abstract

A large proportion of the world's population is at risk of developing symptoms of zinc deficiency due to its low levels in food. The objective of this research was to estimate the heritability in early hybrid generations for the zinc content character in seeds of common bean (Phaseolus vulgaris L.), to investigate possible maternal effects on zinc contents and to evaluate the potential for genetic improvement. Reciprocal F 1 , and F 2 generations as well as backcross (RCP 1 and RCP 2 ) populations were produced by crosses of three cultivars. The seed zinc content was measured by the nitric-perchloric digestion method and using the atomic absorption spectrophotometer. The range of variation in zinc content among tested progenies was from 21.76 mg kg -1 dry matter to 53.48 mg kg -1 dry matter, and no significant maternal effect was discovered. Narrow sense heritability was of an intermediate 57.5% to high 77.84% value and transgressive segregation was observed. These results suggest that breeding for increased zinc content in the seeds of common bean can be quite successful; an increase of 37.3% was obtained using just the three parents tested in this study.

<b>Genetic parameters of iron and zinc concentrations in Andean common bean seeds

“…This result indicates the absence of a maternal effect and that the seeds of the F 1 generation represent fertilization between the parents in both hybrid combinations. Our results agree with those of Possobom et al (2015) and Rosa et al (2010), who reported non-significant maternal effects for iron and zinc concentrations, respectively, in hybrid seeds of common bean.…”

“…Recombinants with higher and lower iron and zinc concentrations in seeds than in the parents were obtained from both hybrid combinations, similar to the results reported for other bi-parental crosses that have been carried out in common bean (Jost et al, 2009;Rosa et al, 2010;Silva et al, 2013;Ribeiro et al, 2014b;Mukamuhirwa et al, 2015;Possobom et al, 2015).…”

“…The broad-sense heritability of the zinc concentrations of Andean common bean seeds had a high magnitude (h 2 b= 63.36 to 72.22%), and the narrow-sense heritability had an intermediate (h 2 n= 31.04%; IAC Boreal × Light Red Kidney) to high (h 2 n= 63.60%; Ouro Branco × Light Red Kidney) magnitude. The variation range that was obtained for the broad-sense and narrow-sense heritability estimates of zinc concentrations was similar to that found for Middle American common bean seeds by Rosa et al (2010) and was inferior to the estimates reported by Cichy et al (2005). In this study, a high narrow-sense heritability was observed for the zinc concentration in the cross Ouro Branco × Light Red Kidney, indicating the predominance of additive variance.…”

“…The existence of hybrid vigor was previously described for the iron and zinc concentrations in common bean seeds (Jost et al, 2009;Rosa et al, 2010;Silva et al, 2013). The development of common bean hybrid cultivars is not usual due to the low efficiency that is obtained in controlled crosses, the non-existence of a male sterility mechanism and the low use of seeds for cropping.…”

“…The expression of a maternal effect of iron and zinc concentrations in common bean seeds depends on the evaluated gene pool and the tested hybrid combination (Jost, Ribeiro, Cerutti, Poersch, & Maziero, 2009;Rosa et al, 2010;Silva, Abreu, & Ramalho, 2013;Mukamuhirwa, Tusiime, & Mukankusi, 2015;Possobom, Ribeiro, Domingues, & Casagrande, 2015). Similarly, there is a wide range of variation for narrow-sense heritability and predicted gain with selection estimates for iron and zinc concentrations in Middle American and Andean common bean seeds (Cichy, Forster, Grafton, & Hosfield, 2005;Jost et al, 2009;Rosa et al, 2010;Mukamuhirwa et al, 2015;Possobom et al, 2015).…”