Fig 1.
In vitro mutagenesis, regeneration of HYP-tolerant plantlets, grafting, and production of pods by grafted plants of Huayu 20.
a The somatic embryos formed on the mutagenesis medium (induction medium plus 4 mg/L PYM); b Buds formed after screening on germination medium containing 4 mg/L and then 8 mmol/L HYP; c-d Grafted HYP-tolerant plantlets (the scions are from HYP-tolerant somatic embryos, and the rootstock is cultivar Huayu 23); e An HYP-tolerant plant growing in the field; f An HYP-tolerant plant of the M1 generation that produced pods (the M2 generation) in the field.
Fig 2.
Variation and segregation among the offspring of specific plants derived from the M2 generation of Huayu 20 during the early growth stage.
a Offspring of plant no. 35 and plant no. 43 differed in growth and vigor during the early growth stage; b Offspring of plant no. 34 differed in size; c Huayu 20, the mutagenic parent.
Fig 3.
Variation and segregation among the offspring of specific plants derived from the M2 generation after harvest.
a Offspring of plant no. 42 differed in plant height, flowering habit, and branch number; b Offspring of plant no. 41 differed in plant architecture and branch number; c Offspring of plant no. 36 differed in pod number; d Offspring of Plant no. 36 differed in pod shape; e Pods of Huayu 20 (the mutagenic parent, left) were normal, and pods of offspring of plant no. 42 were catenuliform with segregation in size; f The seed coats of plant no. 42 offspring were purple while those of Huayu 20 were pink.
Table 1.
SOD and POD activities of Huayu 20 and M3 offspring of HYP-tolerant, regenerated plants. Values are means ± SE. The mutants are designated by two numbers separated by a hyphen. The first number refers to the regenerated plant first transplanted in the field. The second number refers to a specific offspring of that plant. Values are means ± SE. Means in a column followed by different letters are significantly different at P < 0.05.
Table 2.
Polymorphic analysis between the mutagenic parent Huayu 20 and 13 mutants by SSR.
Table 3.
Number of M3 generation individuals (derived from the HYP-tolerant, regenerated plants of Huayu20) that produced ≥ 40.0 g of total pod weight per plant.
Fig 4.
Diagram of frequency distribution on quality characteristics of M4-generation seeds.
The contents of protein, oil, oleic acid, linoleic acid, palmitic acid and the value of oleic acid/ linoleic acid (O/L) of Huayu 20 was 26.62%, 53.78%, 49.38%,31.44%, 4.83% and 1.57, respectively. In total, M4-generation seeds from 150 M3-generation mutagenic individuals were used for calculation of quality characteristics.
Table 4.
Variation range on quality characteristics of M4-generation seeds.
Table 5.
Pod weight per plant and main quality characteristics of some M4-generation offspring that produced >60 g pods/plant.
Table 6.
Result comparasion of oil content of some M5-generation individuals with higher oil content between NIS method and residue method.