Male fertility and occurrence of 2n gametes in East African Highland bananas (Musa spp.)

Abstract

The quantity and quality of pollen produced by a genotype are important attributes to be considered in the selection of male parents for breeding. The objective of this research was to determine the quantity and quality of pollen in 13 selected East African Highland bananas (EAHB) in relation to six diploids commonly used as male parents. Pollen quantity was scored on a scale of 0-6 while the variation of pollen stainability along the rachis was determined using acetocarmine glycerol jelly. Actual male fertility was determined by using pollen from the EAHB varieties on M. acuminata spp.burmannicoides, 'Calcutta 4', as the female. The diameter of 200 viable pollen grains was measured under a microscope with the aid of a graduated eyepiece. Significant differences were obtained for mean pollen stainability and pollen diameter. The pollen stainability for diploids was higher than that for the EAHB. Node numbers contributed significantly to variation of pollen stainability in EAHB (P B 0.01) and 'Pisang lilin' (P B 0.001). 'Pisang lilin' and the EAHB varieties had about 100 nodes as opposed to about 200 in other diploids. The EAHB varieties produced less pollen than most of the diploids. The actual male fertility of EAHB varieties was low (1 seed/bunch), compared to that of 'Calcutta 4' (223.3 seeds/bunch) and 'Pisang lilin' (13.7 seeds/ bunch). Although the production of 2n pollen in EAHB varieties was low (0-7%), the potential exists for using them in new breeding approaches.

Effect of high temperature on the production of 2n pollen grains in diploid roses and obtaining tetraploids via unilateral polyploidization

“…This method for determining 2n pollen grains therefore appears to be preferable to the one based on the determination of a single threshold diameter defined by comparing the distribution of the diameter of the pollen grains of a group of diploid and tetraploid cultivars (Crespel et al 2006(Crespel et al , P ecrix et al 2011). An identical rule was previously used in banana by Ssebuliba et al (2008). A significant genotype effect was observed for the production of 2n pollen grains, with Hw20 being a very low producer and the other genotypes being low-level ones, with a production ranging from 0.3% to 1.3%.…”

“…It is assumed that the mode of the distribution of diameter of the pollen grains corresponds to the average diameter of the n pollen grains (Ssebuliba et al. ). In rose, Crespel et al.…”

“…Rule for determining 2n pollen grains: Based on pollen diameter, each pollen grain was classified into diameter range categories differing in length by 3 lm (the diameter categories were as follows: 0.001-3.000 (lm), 3.001-6.000, etc.). It is assumed that the mode of the distribution of diameter of the pollen grains corresponds to the average diameter of the n pollen grains (Ssebuliba et al 2008). In rose, Crespel et al (2006) showed that the diameter of a 2n pollen grain is on average 1.3 times greater than that of an n pollen grain.…”

Safety Assessment of Transgenic Organisms, Volume 4

“…Table 1). A spontaneous doubling of gamete chromosomes from n to 2n apparently facilitated such crossings (Ortiz, 1997b;Raboin et al, 2005;Ssebuliba et al, 2008;Perrier et al, 2009). Experimental crosses in early cytogenetic studies also made hybrids between M. acuminata and M. balbisiana.…”

Mechanisms of sexual polyploidization and inheritance in triploid citrus populations

“…An FDR 2n gamete contains nonsister chromatids, while an SDR 2n gamete contains two sister chromatids (Bretagnolle and Thompson, 1995;Tavoletti et al, 1996;Cai and Xu, 2007). The use of unreduced gametes in plant breeding (Ramanna and Jacobsen, 2003;Dewitte et al, 2012), resulting in the establishment of sexual polyploids, is useful for improvement of crops such as lily (Lim et al, 2004;Barba-González et al, 2004;2005), maize (Rhoades and Dempsey, 1966), potato (Mok and Peloquin, 1975;Jongedijk et al, 1991), rose (Crespel and Gudin, 2003), rye (Lelley et al, 1987), alfalfa (Ortiz and Peloquin, 1991;Barcaccia et al, 2003) and banana (Ortiz, 1997;Ssebuliba et al, 2008).…”