Studies on artificial selection of gametophyte (pollen) in relation to plant breeding in two-rowed barley. I. Selection of some qualitative characters by high temperature treatment of F<SUB>1</SUB> spikelets just before flowering.

Abstract

When some Mendelian populations are grown successively under different conditions for several generations, they come to have diffcrent gene constitutions. The mechanism of this alteration has been mainly explained by occurrence of individual selection in the populations. It is said, however, that gametophyte selection may play an important role in this alteration. This study was conducted to clarify the existence of gametophyte selection by high temperature treatment of F1 Spikelets of tworowed barley just before flovyering. Materials and characters used in this study are shown in Table 1, and these characters were ascertained to be controlled by one gene having no linkage relation among them. Several ears of one F1 plant were put into warm water, 36-39°C, for 4 minutes just before flowering and the remaining ears of the plant were fertilized under natural conditions as the control. Segregation ratios of some qualitative c'haracters in F2 generation of the former were compared with those of the latter. About 30 F1 plants in each cross combination were treated. Segregation ratios of the four characters -awn type, lateral floret type, awn or awnless in lateral floret, and hair or hairless in leaf sheath- in monohybrid and dihybrid F2 generations, agreed with the expected values in both cases of treament and control (cf. Tables 2, 3-a, -b, -c, 4, 5 and 6) .