Recent surveys of wheat genotypes across the world has revealed that soft wheats all have the same pin alleles (pina-D1a; pinb-D1a), while all hard wheats have a mutation in either pina or
pinb (Giroux and Morris, 1998; Lillemo and Morris, 2000; Morris et al., 2001).
Disomic substitution lines TA6642 DS5[A.sup.m](5A) and TA6562 DS5[S.sup.s](5B) were used to incorporate functional copies of Pina and
Pinb into the hexaploid wheat CS.
Abbreviations: ANCOVA, analysis of covariance; ANOVA, analysis of variance; CS, `Chinese Spring'; G x E, genotype x environment; GSP, grain softness protein; PINA,
PINB, puroindoline a and b proteins; RCBD, randomized complete block design; RFLP, restriction fragment length polymorphism; SKCS, single kernel characterization system.
Mwg502 also failed to show linkage with the
PinB locus that cosegregated with the restriction fragment length polymorphism (RFLP)-derived marker mwg502 in previously constructed barley linkage maps (Kleinhofs et al., 1993).
Explorer has normal starch as opposed to partial waxy, and has the
pinB mutation conferring hard seed texture.
Recently, Giroux and Morris (1998) reported that hard wheats do not have the puroindoline A (PINA) protein and do possess a glycine to serine mutation in the puroindoline B (
PINB) protein.
Genes coding for these two proteins, PinA and
PinB, are tightly linked to the Ha locus on chromosome 5D (Jolly et al., 1993; Sourdille et al., 1996) and probably function together as the Ha locus.