Salt0.384Choline Cl0.060

	Hybrid/Variety	Status	CRP centers
1	IIMR-QPM-1530 (QPM)	AVT-II	IIMR
2	IARI-APH-27 (proA)	AVT-II	IARI
3	IARI- APH-1 (ProA)	AVT-I	IARI
4	IARI-APH-2 (ProA)	NIVT	IARI

  Objective-1: Heterotic grouping and development of biofortified maize genotypes (Provitamin A, QPM, Fe, Zn and low phytate) with high grain potential

Provitamin-A:
Traditional maize possesses 1-2 ppm of provitamin-A (proA), constitutes around 3-10% of the total carotenoids which is dominated by non-proA carotenoids such as lutein and zeaxanthin. Mutant allele of crtRB1 that blocks the hydroxylation of beta-carotene enhances proA by 2-10 folds. So far targeted breeding efforts in India have led to the development of crtRB1-based proA rich inbreds that contain 10-15 ppm of proA. However, their numbers and genetic background they are present is very limited (10-12). In order to develop diverse proA rich inbreds and hybrids, 10 elite normal maize inbreds (1-2 ppm of proA and good combiners for grain yield) were crossed with HarvestPlus donor inbred, HP704-22 (15-20 ppm of proA but poor adaptation in Indian conditions). The elite inbreds include viz., UMI1200, UMI1230, BML6Q, BML7Q, LM11Q, LM12Q, LM13Q, LM14Q, AH7000F and AH7000M. The F2 populations of the 10 crosses were genotyped using crtRB1-specific InDel marker. Segregants homozygous for crtRB1 mutant allele were selected (Fig. 1). The F3 families were evaluated during kharif 2017 for their plant-, ear-,
grain- characteristics (Fig. 2) and quality traits.

                        A set of 75 progenies were selected and selfed for estimation of kernel quality traits. Due to the presence of crtRB1 mutant allele, 82% of the non-proA carotenoids in the elite inbreds have been reduced to 27% in the newly derived proA rich lines (Fig. 3). In donor inbred, proA carotenoids constituted 75% of the total carotenoids, while it was only 8% in the elite inbreds. Among newly developed inbreds, 70% of the the total carotenoids were proA fractions. The proA among the elite inbreds varied from 1.2-2.2 ppm, while the same was 20.6 ppm in the donor inbred. The F2-derived progenies possessed high mean proA (15.9 ppm) with a range of 9.4-21.5 ppm. The comparison of donor, recipient and newly derived 75 crtRB1-based progenies are presented in Fig. 4.

 Figure 1: Segregation of crtRB1 alleles (543 bp and 296 bp) in F2 populations. 543 bp allele is favourable, star indicates homozygous individuals with 543 bp allele.

 Figure 2: Ear- and grain- characteristics of selected newly derived proA rich line

 

 Figure 3: Mean proportion of different carotenoid fractions among donor, elite inbreds and newly developed crtRB1-based inbreds. (LUT: lutein, ZEA: zeaxanthin, BC: beta-carotene, BCX: beta-cryptoxanthin)

 Based on the maturity of the newly developed inbreds, a set of 68 newly developed proA rich inbreds were crossed with five proA rich testers (HKI1105-ProA, HKI161-ProA, HKI163-proA, HKI193-1-ProA and CE-16) during rabi 2017-18. The test cross hybrids would be evaluated at multi-locations for grain yield potential and proA. The data would be used for heterotic grouping of the newly derived proA rich inbreds.

 

                                                                                            Figure 4: ProA levels among donor, elite inbreds and newly developed crtRB1-based inbreds.

 

Quality protein maize:

A set of 197 new QPM lines have been developed through introgressing opaque2 alleles in diverse normal genetic backgrounds. The normal inbred lines used in diversification programme were the parental lines of already released productive public sector hybrids. The detail of inbred lines used as donor for opaque2 alleles are given in table 1. During generation advancement, the segregating lines have been selected based on their opaqueness (45-75%) and useful breeding parameters (Fig. 5). At F4 stage they have been planted in high plant density and simultaneously evaluated for tryptophan and protein content. The tryptophan and protein content was ranging from 0.33 to 0.87 and 7.06 to 12.87% respectively. The desirable QPM segregants were selected and advanced to F5 during kharif 2017. The 46 lines were identified with high lysine (>0.65-0.87) and good in per se performance. The newly developed set has been put in crossing programme during spring 2018 using two diverse tester viz., HKI161 and 193-1. The test crosses will be developed and evaluated during kharif 2018. The DQL 266, DQL 99, DQL 278, DQL 122, DQL 97, DQL 267 and DQL 240 were the promising lines with high tryptophan (> 0.75%) content. Further, one QPM hybrid viz., IMHQPM 1530 has completed two years of testing in AICRP maize programme and based on its significant superiority over the best check the same has been promoted for final year of testing in NHZ (Zone-I). The seed of IMHQPM 1530 has been multiplied through hand pollination for further testing in final year AICRP-QPM trials.

 

                                                                                   Table 1. Details of QPM lines used as donors in diversification programme.

 

Inbred	Grain	Grain	Source	Adaptation	Maturity
CML161	Yellow	Flint	G25Q	Lowland	Late
CML170	Yellow	Dent	G26Q	Lowland	Late
CML176	White	Flint	P63	Subtropical	Late
CML181	White	Dent	UWO41	Subtropical	Late