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ble the chromosome number of 2x diploid Lotus species (2n ϭ 2x ϭ 12 or 14) for germplasm transfer to L.Unreduced gametes (2n gametes) from Lotus glaber Mill. (2n ϭ corniculatus: (i) autotetraploid production by colchi-2x ϭ 12) may aid intercrossing with L. corniculatus L. (2n ϭ 4x ϭ 24) to produce progeny with a greater heterotic advantage than progeny cine-induced chromosome doubling of 2x species, and derived from colchicine-induced {7-acetamido-6,7-dihydro-1,2,3,10-(ii) 2n gametes to create 4x interspecific hybrids between tetramethoxybenzo[a]heptalen-9(5H)-one} tetraploid (4x ) L. glaber. 2x and 4x species. Polyploidization can be achieved by The objective of this research was to compare progeny produced from somatic doubling of the chromosomes (asexual poly-4x with 2x (4x-2x ) and 4x with 4x (4x-4x ) crosses and determine if ploidization) or functional production of 2n gametes by 2n gametes had a heterotic advantage over normal gametes derived aberrations in the meiotic process by sexual polyploidifrom colchicine-induced tetraploids. Vegetative cuttings of the 2nzation (Camadro and Peloquin, 1980). Although both gamete-producing L. glaber genotype 204882-1 (2x 204882-1) were modes can double chromosome number, their relative treated with colchicine and successfully yielded an autotetraploid efficacy becomes evident when genetic variability, in-(2n ϭ 4x ϭ 24) of 204882-1 (4x 204882-1). Three randomly chosen breeding, heterozygosity, and epistasis are considered genotypes from the L. corniculatus germplasm MU-81 were used as maternal parents in crosses to 2x 204882-1 and 4x 204882-1. Progeny (Camadro and Peloquin, 1980; Iwanaga and Peloquin, produced from 4x-2x crosses were intermediate to or larger than their 1982). Almost all polyploid angiosperms arose primarily parents in their leaf and flower morphology. Progeny from 4x-4x through sexual reproduction from 2n gametes rather crosses were intermediate to or smaller than their parents in leaf and than through spontaneous doubling of somatic chromoflower size. Size of leaves and flowers of progeny from 4x-2x crosses somes (Harlan and de Wet, 1975). were similar to or larger than 4x-4x progeny. Morphological compari-Amphidiploid development from the interspecific hysons demonstrated that heterotic expression of progeny from 4x-2xbridization of 2x Lotus species followed by colchicinecrosses was greater than progeny from 4x-4x crosses. The results induced autotetraploidy has been successful (Somaroo indicate that the generation of interspecific L. corniculatus ϫ L.

Two genotypes of Lotus tenuis Waldst & Kit. ex Willd. PI 204882, a diploid (2n = 2x = 12), were identified as producing 2n pollen (maximum = 6%). The objectives of this research were: (1) to determine the mechanism(s) of 2n pollen formation in the L. tenuis genotypes and (2) to morphologically describe n and 2n pollen using light and scanning electron microscopy. Meiotic studies revealed that 2n pollen resulted from tripolar spindles during anaphase II of microsporogenesis. The 2n pollen germinated well, although abnormal pollen tubes were observed. The genetic constitution of 2n pollen resulting from tripolar spindles is equivalent to first division restitution (FDR) of meiosis. Fresh and air‐dried pollen samples exhibited differences in size and shape under light and scanning electron microscopy. The size of diploid (2n) pollen was larger than that of haploid (1n) pollen. Normal haploid (1n) pollen was globose‐prolate in shape, while diploid (2n) pollen was tetrahedral in shape.