Breeding Biofortified Pearl Millet Varieties and Hybrids to Enhance Millet Markets for Human Nutrition

Abstract

Pearl millet is an important food crop in the arid and semi-arid tropical regions of Africa and Asia. These regions are home to millions of poor smallholder's households living in harsh agroecology and reported higher prevalence of malnutrition. . Indeed, pearl millet is one of the food crops they continue to grow for their food and nutritional security. Considering inherent high nutritional values and climate resilient nature (drought and heat), demand for pearl millet as food, beside valued for its Stover as a source of livestock fodder, is projected to grow strongly in Asia (India) and Africa (West and Central Africa). Iron (cause anemia) and zinc (cause stunting) deficiencies are widespread and serious public health problems worldwide, including India and Africa. Biofortification is a cost-effective and sustainable agricultural strategy to address this problem. Aim of this review is to provide current status and future directions of pearl millet biofortification for growing nutrition markets. Research on pearl millet has shown that large genetic variability (30-140 mg kg −1 Fe and 20-90 mg kg −1 Zn) available in this crop can be effectively utilized to develop high-yielding cultivars with high iron and zinc densities. Both Open -pollinated varieties (Dhanshakti and Chakti) and hybrids (ICMH 1202, ICMH 1203 and ICMH 1301) of pearl millet with high grain yield (>3.5 tons/ha in hybrids) and high levels of iron (70-75 mg kg −1 ) and zinc (35-40 mg kg −1 ) densities have been developed and released in India. Currently, India growing >70,000 ha of biofortified pearl millet, besides more pipeline hybrids and varieties are under various stage of testing at the national (India) and international (west Africa) trials for possible release. Biofortification program utilized the existing high-Fe lines identified from the mainstream program to serve the immediate objective of developing high-yielding and high-Fe hybrids. Genomic tools will be an integral part of biofortification breeding program particularly to use diagnostic markers and genomic selection for micronutrients. Several biofortified varieties and hybrids released in pearl millet. Till today, no markets to promote biofortified varieties and hybrids as no incentive price and such products aims to address food and nutritional security challenges simultaneously. The demand is likely to increase only after investment in crop breeding and integration into modern public distribution system, nutritional intervention schemes, private seed and food companies with strong mainstreaming nutritional policies. In the non-traditional regions, this will contribute to livestock and poultry feed industry as spill-over benefits to improve nutrition. The following sections of this review describing various aspects of breeding for increased market opportunity of this crop towards addressing micronutrient malnutrition.

Genome-wide association study uncovers genomic regions associated with grain iron, zinc and protein content in pearl millet

“…Three to fourfold significant variations for Fe (32–120 mg kg −1 ), Zn (19–87 mg kg −1 ) and twofold variation for PC (8–16%) in 281 elite inbred lines prospects the breeding feasibility (Supplementary Table S5 ). Similar variability for Fe/Zn has been reported among germplasm 32 , breeding lines 15 , and commercial cultivars 33 . High genetic variance for Fe/Zn indicates the least influence of G × E. Population structure along with shared co-ancestry coefficients between individuals of subdivisions of a population were estimated using ADMIXTURE 1.23 73 .…”

“…The wide variability for grain Fe and Zn content in pearl millet unveils the great prospect of developing biofortified pearl millet varieties and hybrids. The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) has been working towards developing biofortified hybrids and has successfully delivered high-Fe pearl millet varieties and hybrids with high yield potential in India and Africa 15 . Biofortification using conventional breeding is time-consuming and incurs a high cost in terms of screening hybrid parental lines for micronutrients and protein in every generation.…”

Exploitation of Heterosis in Pearl Millet: A Review

“…However, A 1 , A 4 , A 5 are widely used in the three-line breeding program for the production of hybrid seeds. Nowadays, hybrid development has led away from the A 1 CMS source, but interestingly, the pearl millet bio-fortification program used both A 1 and A 4 CMS sources to release different hybrid varieties [ 128 ].…”

“…In 2005, HHB 67 Improved was the first product of marker-assisted selection (among all crops) released in India. To address widespread problems of micronutrient malnutrition, ICRISAT developed high-iron bio-fortified hybrids named ICMH 1202, ICMH 1203 and ICMH 1301 [ 128 ]. In India, a total of 138 hybrids were released by both the public and private sectors from 1958 to 2014 [ 129 ].…”

“…The latter has played a significant role in the development of high-yielding disease-resistant heterotic hybrids. These private companies produce their proprietary hybrids with yield and consumer preference-related traits [ 128 ]. Moreover, the private sector utilizes ICRISAT-bred component lines (CMS, maintainer, and restorer lines) for hybrid seed production.…”