The Genetical Control of Incompatibility in Phalaris Coerulescens Desf.

Abstract

Pha/a1'is roau/c8CeJ18 Des!'. is a completely Relf-incompatible, diploid, perennial gmss. incompatible pollen gmins germinate normally but the pollen tubes fail to penetrate far into tho 8Lyle. The ineompatibility interrelationships of parents and progenios were dotermined by olmen-ing the pollen tubes and pollen grains after pollination. This eould be clone successfully only in plants induced to Hower early by eXJlosure to 100tg day treatment. Incompatibility is controlled by two loci, each with a series of multiple alleles. The loci are probably not linked but the data would not. allow detection of loose linlmge. Pollen determination is gametophytic, and the genes aet indepoudelltly in the style. 'eho rolationship of this incompatihility system to previously described systems is eonsid(lred, and theoretically possible incompatihility systems based on genetical eOlltrol nt. two loci are suggested.