การปรับปรุงพันธุ์ลูกผสมชั่วที่หนึ่งของผักกาดเขียวปลี โดยใช้การผสมตัวเองไม่ติดและเป็นหมันที่ควบคุมโดยยีน ในไซโทพลาซึม

Abstract

The F1 hybrid improvement of leaf mustard was attempted through self-incompatibility (SI) and cytoplasmic male sterility (CMS) mechanisms, with the use of seed set per pod to determine the levels of pollen viability and self-incompatibility. The objective was to select a parental line for producing F1 hybrid seeds that produce crops with good horticultural characteristics for food industrial processing. The results of pollen viability analysis indicate that BC9(4-4x2M)G3, BC9(4- 4x2M)J11, BC9(4-4x40R)L4, BC11(4-4x4OR) and BC9(4-3x19H)P7 are of empty pollen or CMS type while the 40R-2, 40R-17, 2M-3, 2M-23, 19H9-9, and 19H116 are in the male fertile group. The self-incompatibility analysis by seed counts showed that 40R-17, 2M-23 and 19H9-9 belong to the weak-self-compatibility (WSI) group. The evaluation of the F1 hybrid from CMS maternal lines reveals that BC11(4- 4x40R)x40R-2 has a high total yield weight of 3,456 kg/rai. However, the yield weight after trimming per plant is too high to be suitably used for food industrial processing as the weight acceptable by the processing plants is in the range of 250-350 grams per plant. The hybrids BC9(4- 4x40R)L4x40R-17, BC9 (4-4x2M)G3x19H16, BC9(4-4x2M)J1 1x2M-3, BC9(4-4x2M)G3x40R-2, BC9,(4-4x2M)G3x19H9-9, BC11(4-4x40R)X40R-17, BC9(4-3x19H)P7x19H16, BC9(4-3x19H)P7x 40R-2, BC11(4-4x40R)x2M-23, BC9(4-3x19H)P7x19H9-9, BC11(4-4X40R)x19H9-9, BC11(4-4x 40R)x19H16 and BC9(4-3x19H)P7x2M-23 however, have suitable yield weight per plant for processing. The mean heterosis over the parental lines for yield per rai was found to be both positive and negative. BC9(4-3x19H)P7x40R-2 showed high positive heterosis at 42.9 percent while BC9(4- 4x2M)J11x40R-17 showed high positive heterobeltiosis at 36.5 percent. Furthermore, BC9(4- 4x40R)L4x 19H9-9 showed high negative heterosis over the commercial varieties at -40.9 percent. The evaluation of the F, hybrid from SI maternal lines reveals that 19H16x2M-3 showed a high yield weight of 2,935 kg/rai, significantly different from the parental line and some commercial varieties except for the Standard 1 commercial variety. The hybrids 2M-23x19H16, 40R-2x2M-23, 2M-3x19H9 and 40R-17x2M-3 gave the weight after trimming at 343, 342, 340, 315 and 284 gram, respectively, and their weights per plant satisfy the factory requirement. The hybrid 40R-17x2M-3 had heterosis in yield weight per rai, with high negative heterosis at -21.6 percent. Moreover, it showed high negative heterobeltiosis at -32.3 percent and high negative heterosis over the standard variety at -27.8 percent. The evaluation of horticultural characteristics at 55 days after transplant found that the F1 hybrids have good horticultural characteristics that precisely meet the food industrial processing requirements. However, these F1 hybrids had a lower yield weight relative to the commercial varieties. Besides, some hybrids produced loose heading which was the result of the backcross with the maternal line failing to generate the best and complete heading in F1. Thus, there remains a need for more improvement to achieve both firm heading and high yield in leaf mustard.