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Waxy corn possessing high amylopectin is widely employed as an industrial product. Traditional corn contains ~ 70–75% amylopectin, whereas waxy corn with the mutant waxy1(wx1) gene possesses ~ 95–100% amylopectin. Marker-assisted breeding can greatly hasten the transfer of the wx1allele into normal corn. However, the available gene-based marker(s) for wx1are not always polymorphic between recipient and donor parents, thereby causing a considerable delay in the molecular breeding program. Here, a 4800 bp sequence of the wx1gene was analyzed among seven wild-type and seven mutant inbreds employing 16 overlapping primers. Three polymorphisms viz., 4 bp InDel (at position 2406 bp) in intron-7 and two SNPs (C to A at position 3325 bp in exon-10 and G to T at position 4310 bp in exon-13) differentiated the dominant (Wx1) and recessive (wx1) allele. Three breeder-friendly PCR markers (WxDel4, SNP3325_CT1, and SNP4310_GT2) specific to InDel and SNPs were developed. WxDel4 amplified 94 bp among mutant-type inbreds, while 90 bp was amplified among wild-type inbreds. SNP3325_CT1 and SNP4310_GT2 revealed the presence-absence polymorphisms with an amplification of 185 bp and 189 bp of amplicon, respectively. These newly developed markers showed 1:1 segregation in both BC1F1and BC2F1generations, while 1:2:1 segregation was observed in BC2F2. The recessive homozygotes (wx1wx1) of BC2F2identified by the markers possessed significantly higher amylopectin (97.7%) compared to the original inbreds (Wx1Wx1:72.7% amylopectin). This is the first report of novel wx1gene-based markers. The information generated here would help in accelerating the development of waxy maize hybrids.

Sweet corn has gained worldwide popularity. Traditional sweet corn possesses low concentration of essential nutrients such as lysine (0.15–0.25%), tryptophan (0.03–0.04%) and provitamin-A (proA 3–4 ppm), and deficiency leads to serious health problems in humans. Here, stacking of shrunken2(sh2), opaque2(o2), lycopene epsilon cyclase (lcyE) and β‐carotene hydroxylase(crtRB1) genes  were undertaken in the parents of four hybrids viz., APQH1, APHQ4, APHQ5 and APHQ7 using marker-assisted backcross breeding (MABB). Gene-linked markers (umc2276and umc1320) for sh2, while gene-based markers for o2(umc1066and phi057), lcyE(5′TE-InDel) and crtRB1(3′TE-InDel), were used for genotyping in BC1F1, BC2F1and BC2F2. Selected backcross progenies showed high recovery of recurrent parent genome (92.4–97.7%). The reconstituted sweet corn hybrids possessed significantly high lysine (0.390%), tryptophan (0.082%) and proA (21.14 ppm), coupled with high kernel sweetness (brix 18.96%). The improved sweet corn hybrids had high cob yield (12.22–15.33 t/ha) across three environments. These newly developed biofortified sweet corn hybrids possess great significance in providing balanced nutrition. This is the first report of combining sh2, o2, lcyEand crtRB1genes for enrichment of sweet corn hybrids with multiple essential nutrients.