Blue aleurone trait diagnoses developmental origin of three pistils in a floret in common wheat.

The common 'three-pistil' (TP) wheat mutation line expresses TPs in a floret normally containing TPs forming three grains set close back-to-back. The developmental origin of the TP trait in common wheat had been diagnosed non-destructively using the blue aleurone trait. The aleurone colour of F2 seeds grown in F1 plants of cross TP/UC66049 was evaluated. Due to xenia, the hue of blue grain colour depended on dose of the Ba1 gene for blue aleurone in the triploid endosperm. The TP trait produced four types of segregation in three-seed clusters: (i) white grain only, (ii) two white grains and one blue, (iii) one white grain and two blue, and (iv) three blue grains only. The observed frequency of blue-white seed within clusters followed the binominal distribution 3Cr (0.75)r∙(0.25)3-r, where r is the number of colour variants in three-seed clusters (r = 0-3). Intrafloret segregation of seed colour and F2 segregation derived from aleurone colour of F3 seeds indicated an independent origin of the TP trait. [ABSTRACT FROM AUTHOR]