Cassava is an important food crop in tropical regions, and one of the main breeding goals is to cultivate new lines with high β-carotene, low cyanogenic glucoside and waxy taste. In order to screen promising edible lines from breeding materials, the study developed a MATE-SNAP marker based on a mutation of G→A in the coding region of cyanogenic glucoside transporter gene MATE which resulted to amino acid change and affected its transmembrane structure stability. Combining with the β-carotene PSY2-SNAP and waxy quality GBSSⅠ-SNAP markers, 12 parent lines, carrying 1-2 target alleles, were selected from 50 cassava germplasms, and totally hybridized 10 cross-combinations according to flowering period among different years. Firstly, 134 erect or middle branched candidate lines were screen out through seedling, transplanting and preliminary field trial. Secondly, 13 edible promising lines which aggregated 2-3 target alleles, were chosen by using MATE/PSY2/GBSSⅠ-SNAP markers together. The content of of cyanogenic glucoside in root flesh was determined by spectrophotometry, the value of SC9 was 49.24 μg/g, and those of 13 promising lines were in the range of 38.82-76.51 μg/g; the content of β-carotene in root flesh was determined by acetone colorimetry, the value of SC9 was 184.75 μg/hg, and those of the six yellow-root lines were within the limits of 101.58-154.10 μg/hg; the content of amylopectin in root flesh was determined by dual wavelength spectrophotometry, the values of P13-1 and V7-14, whose alleles were GG that genotyped by GBSSⅠ-SNAP marker, was 82.46% and 83.79%, respectively. Based on this, 5 lines, A5-138, A2-213, P7-6, V4-8 and V4-19, were found to be the potential new edible cassava varieties by taste grading. In conclusion, marker-assisted selection can quickly and accurately screen out the target lines from breeding materials and improve the efficiency of cassava genetic improvement.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |