A method for producing a hybrid maize plant, plant material or seed that has enhanced vigor in comparison with a conventional mutant shrunken-2 hybrid maize plant, plant material or seed and one or more additional desirable traits, including an enhanced ability to retain sugar over a period of time following a prime eating stage thereof, in comparison with a conventional mutant sugary-1 or shrunken-2i hybrid maize plant, plant material or seed, comprising the following steps:
- (a) identifying an inbred maize plant line that includes one or more desired mutant endosperm alleles in its genome, singly or in combination, optionally using one or more molecular markers, wherein the mutant endosperm alleles are sugary-1 (su1), sugary enhancer-1 (se1) or shrunken-2 (sh2), or any combinations thereof;
- (b) constructing one or more female near isogenic maize plant lines having a desired genotype for use as a genetic background in a combination with a female parental maize plant line that includes a shrunken-2i (sh2-i) mutant endosperm allele in its genome;
- (c) incorporating a shrunken-2i mutant endosperm allele into the genome of the female near isogenic maize plant line having the desired genetic background of step (b), optionally using one or more molecular markers, wherein the desired genetic background is Su1Su1 se1se1, Su1Su1 se1se1 sh2sh2, Se1Se1 su1su1, Se1Se1 su1su1 sh2sh2, su1su1 se1se1, su1su1 sh2sh2, se1se1 sh2sh2, su1su1 se1se1 sh2sh2, or another desired genetic background including in homozygous recessive condition the sugary-1 and/or sugary enhancer-1 mutant endosperm alleles;
- (d) selecting a female converted near isogenic maize plant line of step (c) having a shrunken-2i mutant endosperm allele incorporated into the genetic background of step (c), wherein the female converted near isogenic maize plant line includes an endosperm allelic combination of Su1Su1 se1se1 sh2-i sh2-i, Se1Se1 su1su1 sh2-i sh2-i, su1su1 se1se1 sh2-i sh2-i, su1su1 sh2-i sh2-i, se1se1 sh2-i sh2-i, or another desirable endosperm allelic combination of the shrunken-2i mutant endosperm allele in homozygous condition together with either or both of the sugary-1 or sugary enhancer-1 mutant endosperm alleles each in homozygous condition, in its genome;
- (e) crossing the selected female maize converted near isogenic plant line of step (d) with a male maize plant line that does not include a shrunken-2i mutant endosperm allele in its genome, and that includes a double homozygous recessive endosperm allelic construction in its genome, wherein such double homozygous recessive endosperm allelic construction is Su1Su1 se1se1 sh2sh2, su1su1 Se1Se1 sh2sh2, su1su1 sh2sh2, se1se1 sh2sh2, or another double homozygous recessive endosperm allelic combination including either the sugary-1 or sugary enhancer-1 mutant endosperm alleles together with the shrunken-2 mutant endosperm allele, that can provide a hybrid maize plant with a high or enhanced eating quality;
- to produce a hybrid maize plant comprising the allelic construction sh2 sh2-i at the shrunken-2 locus and homozygous recessive alleles at either or both of the su1 and se1 loci, said hybrid maize plant having one or more desired grower traits, consumer traits, or both traits;
- (f) optionally, examining a physical appearance of seeds or kernels produced by the maize plants of step (d), step (e), or both step (d) and step (e), for characteristics including smoothness, fullness or relative weight, or a combination thereof;
- (g) optionally, conducting one or more warm, cold, or both warm and cold, laboratory, field, or laboratory and field, germinations of seeds or kernels produced by the maize plants of step (d), step (e), or both step (d) and step (e), to verify that such seeds or kernels have one or more desired consumer or grower traits, or a combination thereof;
- and
- (h) optionally, conducting one or more organoleptic taste, pericarp tenderness or other tests on maize plants, or plant parts, or a combination thereof, that are grown from seeds or kernels produced by the maize plants of step (d), step (e), or both step (d) and step (e), to determine their taste, pericarp tenderness or other organoleptic characteristics, or a combination thereof;
- wherein the hybrid maize plant, plant material or seed has an enhanced vigor in comparison with a conventional mutant shrunken-2 hybrid maize plant, plant material or seed;
- and wherein the hybrid maize plant, plant material or seed has an enhanced ability to retain sugar over a period of time following a prime eating stage thereof in comparison with a conventional mutant sugary-1 or shrunken-2i hybrid maize plant, plant material or seed.