Fig 1.
Grafted S1 plant (left) and non-grafted S2 seedling (right) grew normally.
The arrow indicates the grafted part of the plant shown on the left.
Fig 2.
Genomic in situ hybridization showing the chromosome components of an S2 mitotic cell of the new synthetic allotetraploid (Slides were stained in 4’, 6-diamidino-2-phenylindole [DAPI]).
Red signals indicate the 26 chromosomes of G. australe (probe labeled with digoxigenin-11-dUTP) and blue signals indicate the 26 chromosomes of G. herbaceum (stained with DAPI).
Table 1.
Chromosome configurations of pollen mother cells at Metaphase I of meiosis.
Fig 3.
Chromosome associations in PMCs at Metaphase I of meiosis.
a, 25II + 2I; b, 24II + 4I; c, 25II + 2I; d, 23II + 3I + III; e, 24II + I + III. Arrows indicate the univalents and arrowheads indicate the trivalents. Bar = 10 μm.
Table 2.
Morphological characters of interspecific hybrid F1, S1 and their parents.
Fig 4.
Flowers of the new synthetic allotetraploid and its parents.
a-1, G. herbaceum; a-2, G. australe; a-3, interspecific hybrid F1; a-4, S1. b, G. herbaceum; c, G. australe; d, interspecific hybrid F1; e, S1. Bar = 25 mm.
Fig 5.
Seed kernels of G. herbaceum (1), G. australe (2) and the new synthetic allotetraploid S1 (3).
Numerous pigment glands on the cotyledon surface of G. herbaceum (1); no pigment glands on the cotyledon surface of G. australe (2); a few pigment glands on the cotyledon surface margin of the synthetic allotetraploid S1 (3).
Fig 6.
Leaf shapes from left to right: G. herbaceum (1), G. australe (2) and the synthetic allotetraploid S1 (3) and S2 (4).
Bar = 25 mm.
Fig 7.
Validation of the new synthetic allotetraploid of G. herbaceum × G. australe using a randomly selected set of polymorphic SSR primers.
From a to h, polymorphic amplicons of F1, S1, S2 and its parents were detected using SSR primers NAU207, NAU704, NAU905, NAU2325, NAU3995, NAU7751, NAU7699 and NAU6064, respectively. Here, showed eight codominant markers. P1, G. herbaceum; P2, G. australe; F1, G. herbaceum × G. australe; S1, synthetic allotetraploid of G. herbaceum × G. australe; S2, progeny from S1 self-pollination; M, molecular marker sizes (100 bp ladder).
Fig 8.
A strategy for the development of varieties with the trait of high-gossypol plants with low- gossypol seeds.