GENETIC DIVERSITY IN TRADITIONAL GENOTYPES FOR GRAIN IRON, ZINC AND Β-Carotene CONTENTS REVEAL POTENTIAL FOR BREEDING MICRONUTRIENT DENSE RICE

Abstract

Rice is the staple food for half of the world"s population, however, its edible grain part is deficient in essential micronutrients, especially Fe and Zn. Breeding for micronutrient dense rice demands exploration of available genetic diversity for grain Fe, Zn and β-carotene contents. In this study, we analysed brown and polished grain samples of 26 traditional rice genotypes for Fe and Zn concentration. Fe concentration varied from 13.23 ppm to 45.83 ppm and 1.10 ppm to 36.45 ppm in brown and polished rice, respectively. Whereas, Zn concentration in brown and polished rice ranged from 18.67 ppm to 38.01 ppm and 5.86 ppm to 23.88 ppm, respectively. The landraces had higher Fe and Zn contents than improved varieties and advance uniform lines. Significant positive correlation was present between Fe and Zn concentration in brown (r = 0.694, P < 0.01) and polished rice (r = 0.533, P < 0.01). Fe concentration was greatly reduced by the polishing process than Zn concentration and approved varieties lost less Fe and Zn contents than advance uniform lines. Minimal levels of beta-carotene were detected in rice genotypes indicating need for genetic modifications to enhance pro-vitamin A contents in rice endosperm.

Grain Fe and Zn contents linked SSR markers based genetic diversity in rice

“…Furthermore, the practice of consuming polished rice grains in Asian populations aggravates malnutrition [8]. During recent past, proper attention has been given to improve rice grain Fe and Zn contents, as wide genetic variability for these essential micronutrients have been reported in natural rice germplasms [9][10][11][12][13][14]. Plant breeding based biofortification is the most cheaper and sustainable approach to improve grain micronutrient contents and eradicates malnutrition from rice-eating poor populations [15].…”

Grain Fe and Zn Contents Linked SSR Markers Based Genetic Diversity Reveal Perspective for Marker Assisted Biofortification Breeding in Rice

“…During recent years, SSR markers based genotyping has proven to be very useful for exploring a variety of surreptitious information in plants, ranging from domestication traits to crop improvement through marker-assisted breeding [37][38][39][40]. Although, individual reports on micronutrient density and SSR based genetic diversity in rice have been recently published [10,12,13,36,41], however, to date, a combined study of grain Fe and Zn contents and trait linked SSR markers based genetic diversity is obscure.…”

“…Overall, these results indicate the prevalence of wide genetic variability in studied rice accessions for grain Fe and Zn contents and possibility of their simultaneous improvement. However, mineral densities in polished or white rice need to be assessed before utilizing these accessions in rice biofortification breeding programs, as loss of significant quantities of both micronutrients have been reported during the polishing process [12,36,47].…”

“…The seed of these accessions was obtained from Rice Research Institute, Kala Shah Kaku (RRI, KSK), Pakistan and International Rice Research Institute (IRRI), Philippines. All accessions were planted under natural field conditions at the experimental area of RRI, KSK during two cropping seasons 2017-18 and 2018-19, as previously described [12]. The seed obtained from these experiments was used for estimation of Fe and Zn contents.…”

“…Furthermore, the practice of consuming polished rice grains in Asian populations aggravates malnutrition [8]. During recent past, proper attention has been given to improve rice grain Fe and Zn contents, as wide genetic variability for these essential micronutrients have been reported in natural rice germplasms [9][10][11][12][13][14]. Plant breeding based biofortification is the most cheaper and sustainable approach to improve grain micronutrient contents and eradicates malnutrition from rice-eating poor populations [15].…”