 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Performance of Testcross Hybrids of Semi-exotic Inbred Lines
Contained Different Proportions of U.S. Corn Belt Germplasm) ผู้เขียน: ดร.กฤษฎา สัมพันธารักษ์, ศาสตราจารย์ ,  Putu Darsana สื่อสิ่งพิมพ์:pdf AbstractU.S. Corn Belt germplasm including 8 hybrids, 5 open pollinated varieties, 5 BSSS and 4 non-
BSSS inbred lines were introduced and subsequently crossed and backcrossed to 6 tropical inbred lines
namely Nei9008, Nei9202, AMATLC0HS 63-2-5-E-3-1-2, AMATLC0HS 170-2-3-2-1-1-1-B-3, Ag18
and Ki42 to adjust the proportion of exotic germplasm to 50 and 25 % of each of the tropical lines. Semiexotic
inbred lines were extracted from the 48 groups of adjusted exotic germplasm (6 tropical lines ? 4
exotic groups ? 2 exotic proportions). Subsequently, the resulted 48 BC0S3 and 48 BC1S2 were crossed
to 2 tropical inbred testers, Ag20 (high general combining ability) and Ag29 (high specific combining
ability). The experimental results revealed that the hybrids were the most promising exotic sources for
desirable alleles followed by non-BSSS inbred lines and OPV’s, respectively. In addition, 25% exotic
inbred lines performed better than the 50% exotic inbred lines in combinations with the 2 testers. Testcross
hybrids of Ag20 out performed the testcross hybrids of Ag29. All top-10 testcross hybrids were derived
from crosses involving with Ag20. The top-6 testcross hybrids which yielded statistically non-significant
differences from the best tropical hybrid check were derived from semi-exotic inbred lines involving with
each of the 6 tropical recurrent inbred lines with donor parents from exotic hybrids and non-BSSS inbred
lines, except one combination from BSSS inbred lines. The results suggested that highly improved
hybrids and inbred lines were the most promising exotic sources. Different testers gave different results
and therefore, the best testers should be the intended inbred counterpart in the new hybrid combinations
or otherwise the appropriate method should be selection for performance per se of inbred lines followed
by diallel cross of selected lines. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Genetic Potential of Exotic Germplasm Introduced from
Different Latitudes for the Improvement of Tropical Maize
(Zea mays L.)) ผู้เขียน:Putu Darsana, ดร.กฤษฎา สัมพันธารักษ์, ศาสตราจารย์, เอนก ศิลปพันธุ์ สื่อสิ่งพิมพ์:pdf AbstractTo broaden the genetic base of the tropical maize, adding more favorable alleles from exotic
germplasm into the tropical breeding material is one way suggested by plant breeder. For effective
utilization of the exotic germplasm, rapid and efficient method of incorporation of exotic germplasm into
tropical material is needed. This study was conducted to assess a genetic potential and the effectiveness
of exotic germplasm introduced from different latitudes in combination with tropical breeding materials.
The results of the study implied that: semi-exotic populations containing 50 % exotic germplasm showed
the lowest yield, lowest grain moisture content, earliest days to anthesis and silking, highest leaf disease
infection. Semi-exotic populations with 25 % and 12.5 % exotic germplasm showed no significant
difference to population with 0 % exotic germplasm, except semi-exotic population of latitude-2 (> 22.5
– 37.5 ?North Latitude), Southern U.S. germplasm. Significant quadratic response among population
means due to proportion of exotic germplasm was noted for grain yield of the semi-exotic populations
of latitude-1 (> 37.5 ?N.L.), -2, -3 (> 7.5 – 22.5 ?N.L.), and -5 (> 37.5 ?South Latitude). Significant linear
responses were noted for days to anthesis and silking and grain moisture content. Highly significant linear
response to leaf diseases was observed in semi-exotic populations of latitude-1, -2, -3, -4 (> 22.5 –
37.5 ?S.L.), and significant response was shown by exotic source from latitude-5. Population with 50 %
exotic germplasm from latitude-4 “South Africa” was well adapted to tropical condition and showed no
response to the higher degree of tropical germplasm. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Study of Maize Populations Contained Different Proportions of U.S. Corn Belt Germplasm) ผู้เขียน:ดร.กฤษฎา สัมพันธารักษ์, ศาสตราจารย์, Putu Darsana สื่อสิ่งพิมพ์:pdf AbstractThe incorporation of exotic germplasm into tropical breeding materials can broaden and diversify the genetic base of the tropical maize, and also adding more desirable alleles. For effective utilization of the exotic germplasm, choice of exotic source and efficient method of incorporation of exotic germplasm into tropical material is needed. This study was conducted to asses a genetic potential and the effectiveness of different types of exotic germplasm introduced from U.S. Corn Belt in combination with tropical breeding materials. The results of the study implied: commercial hybrid was the most promising source to improve performance of the tropical inbred lines followed by Non-BSSS inbred lines and BSSS “Iowa Stiff Stalk Synthetic” inbred lines. Semi-exotic population with 50% exotic showed significantly lower grain yield, earlier days to silking and anthesis, lower grain moisture content and higher leaf disease infection than 25 and 12.5 % exotic. On the other hand, no significant difference was observed between 25 and 12.5 % exotic. Semi-exotic pipulations with 25 and 12.5 % commercial exotic hybrid also showed grain yield higher than the corresponding tropical population but were not statistically different to the best check variety “Suwan 1”. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Development of Semi-exotic Maize (Zea mays L.) Inbred Lines: Performance per se and in Hybrid Combinations) ผู้เขียน:Putu Darsana, ดร.กฤษฎา สัมพันธารักษ์, ศาสตราจารย์, เอนก ศิลปพันธุ์ สื่อสิ่งพิมพ์:pdf AbstractTo create positive transgressive segregation of quantitatively inherited traits such as yield of inbred lines, two or more sources which accumulate different classes of favorable alleles are required. Introgression of exotic germplasm into tropical inbred line is one of several possible methods. This study was conducted to asses a potential use of exotic germplasm introduced from different latitudes to improve tropical inbred lines and their performance in hybrid combinations. The results of the present study indicated that all improved exotic germplasm were equally useful as sources of desirable alleles, especially for high yield of semi-exotic inbred lines. The 25 % semi-exotic inbred lines showed earlier days to anthesis and silking, lower grain moisture content, but higher leaf disease infection than the 12.5 % semi-exotic inbred lines. Transgressive segregation of semi-exotic inbred lines was also found in each class of exotic germplasm. Testcross hybrids generated from crossing between tropical testers with 12.5 % exotic inbred lines showed higher yield, earlier maturity, and better disease resistance than the testcross hybrids of 25 % exotic inbred lines. Result of the present study suggested that combining ability of recurrent parent and the tester as well as proportion of exotic alleles in the converted semi-exotic lines are very importance for a success of semi-exotic inbred lines in hybrid combinations. |