Variation in pollen fertility and chromosome number among germplasm collections of ginger (Zingiber officinale Rosc.)

Abstract

Pollen fertility in 21 germplasm collections of ginger was determined by glycero-carmine staining and in vitro germination. Pollen fertility based on staining ranged from 5.59% to 67.73%, while in vitro germination ranged from 2.35% to 60.31% in different collections analyzed. High pollen stainability was not always followed by high in vitro germination in collections analyzed. However, the in vitro germination percentage was always lower than the percentage of stainability in all the collections. Highest in vitro pollen germination was recorded in acc. no. 195 (60.31%) followed by acc. no. 821 (50.67%). Somatic chromosome number analysis of the collections revealed that the two collections with high pollen fertility (acc. nos. 195 and 821) were tetraploids with 2n = 44 while most of the other collections had 2n = 22, the normal chromosome number. One collection with aneuploid chromosome number of 2n = 24 had lower pollen germination (4.82%), similar to many diploid collections. Tetraploids are identified for the first time from germplasm collections of ginger. The role of polyploidy in improving pollenfertility in ginger is discussed.