Phenotype characterization and genetic analysis of brittle culm mutants of IR64 and TNG67 varieties

• Main Authors: Tsung-Han Tsai, 蔡宗翰
• Other Authors: 王強生
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/88332268782619572942

碩士 === 國立中興大學 === 農藝學系所 === 99 === The mechanical strength of crop is an important agronomic trait, less mechanical strength makes lodging or breaking of plants and results in tremendous yield loss. Four brittle levels of leaves or culms were defined as 0 (non-brittleness), 1 (slight), 3 (moderate) and 5 (extreme) according to the cracking point by hand-bending in this study. Accordingly, 13 brittle mutants were screened during M1 to M4 generations from the indica type mutant pool of IR64 variety developed by sodium azide mutagenesis. Finally, 9 mutants with level 5, 2 mutant with level 3, and 2 mutants with level 1 brittleness respectively, were obtained at the M9 generation. Two pure lines, IRB3 (normal plant type, level 3 brittleness) and IRB12 (dwarf, level 5 brittleness), were selected in M5 for anatomical analysis. The results showed that the distance between vascular bundles of mutants were shorter than of IR64 ones and the brittle mutants also had less width in bulliform cell in leaf. Similarly, in the culm of brittle mutants, shorter distance between vascular bundles and thickness of cell wall were also observed than of IR64 ones. The IRB3 mutant was crossed with TNG67 to investigate the inheritance of brittleness. Their hybrids were screened by polymorphic SSR markers and no brittleness was found in F1. The brittleness of leaf and culm in the F2 population were determined and Chi-squared analysis analyzed, the results displayed that the brittleness of IRB3 was governed by a single recessive gene. Twelve pure brittle mutants were selected from a japonica mutant pool of TNG67 variety. Four lines, SA1067, SA1551, SA1566 and SA1610, were crossed with TNG67 and processed to F2. The genetic analysis suggested that the brittleness of these mutants were controlled by a single recessive gene. Allelic test was conducted by crossing between mutants and the brittleness of plants was investigated. All the F2 of SA1551/SA1610 showed brittle culms indicated that they were mutated at the same locus. However, the non-brittle vs. brittle ratio of F2 populations in the crosses of SA1067/SA1551, SA1067/SA1610, SA1551/SA1566 and SA1566/SA1610 fitted 9:7 suggested that the brittleness trait of these mutants were mutated or controlled by different genes. Molecular investigation of these mutants will provide valuable information for sodium azide mutagenesis as well as the applications.