PLOIDY DETERMINATION IN MUSA GERMPLASM USING POLLEN AND CHLOROPLAST CHARACTERISTICS

We attempted to determine ploidy level in the gametophyte and the spor ophyte of Musa using pollen and chloroplast characteristics, respectiv ely. In the gametophyte, interploidy differences accounted for 63.8% o f the genetic variance for pollen diameter and 87.5 % for pollen stain ability, the remainder being attributable to intraploidy differences a mong clones. While pollen count and stainability effectively separated triploid accessions from diploids or tetraploids, they did not discri minate between diploids and tetraploids. In the sporophyte, the relati ve contributions of interploidy and intraploidy differences to genetic variation in the number of chloroplasts in stomatal guard cells were 70.8% and 29.2%, respectively. Although pollen diameter and chloroplas t number increased with ploidy, the use of the sporophytic parameter a ppears to provide a more satisfactory means of estimating ploidy statu s in Musa.