Corn (Zea mays.L) is the second leading cereal in Myanmar and an important commodity in earning farmers’ income and foreign currencies. To increase productivity, development of locally adapted better hybrid is strongly needed. For upgrading the hybrid corn research and development program, Department of Agricultural Research (DAR) invited the International Corn Foundation (ICF)/Kyungpook National University (KNU) in 2005. Under this collaborative program, research on genetic potential of exotic germplasm introduced from Nepal, Hawaii, Korea, China and IITA has been carried out in 2009 rainy season. Yield trials of 108 and 80 combinations of Myanmar lines and exotic germplasm (Normal × Normal crosses, Normal × Super-sweet) were carried out in Tatkone, Yezin (central zone), Nyaung Mon (north zone), Aung Ban (highland zone) research stations, respectively. These experimental crosses are produced in Korea and Cambodia, 2008. Two to five outstanding hybrids have been selected for three respective zones. Selected hybrids yielded 50-100% more than the best commercial hybrid, CP888 imported from Thailand.The hybrids are tolerant to Rhizoctonia blight in the Tatkone, Exserohilum turcicum blight in Aung Ban, and E. turcicum and stem borers in the Nyaung Mon. A couple of normal super-sweet corn hybrids were selected for nutrition, sugar and vitamin A+. These results point out that introgression of exotic alleles has a potential to increase the heterotic response in yield and biotic resistance. Thus, an understanding of the heterotic relationship between adapted and exotic is needed to exploit exotic germplasm intelligently.

We studied on the diallel cross analysis of three different types of corn(Zea mays L.); supersweet(ss), sticky waxy and normal field corn in Korea and China. Four inbred lines each of three different types were crossed in a full diallel. Testing of 66 F1 crosses were made at two locations in Korea and China, respectively, in 2009. The objectives of the experiment was first to study different levels of heterosis among three types. In Korea, average ear length of 16 F1 crosses was the longest in N x wx (197mm), followed by wx x ss (193mm) and N x ss (191mm). Average of ss, wx and N were 135mm, 171 mm and 155mm. The relatively high level of N might be location specific breeding results, where the testing was done at the center of waxy corn breeding. Trends of three F1 crosses in China were similar with normal and supersweet corn. The result of this study has supported for breeding of high quality sticky-supersweet and high yield potential of normal -supersweet corn hybrids in the developing world to provide nutrition, sugar and other minerals such as Vitamin A and anthocyanin, simultaneously as a high quality food.

Corn (Zea mays. L) is one of the potential export crops of Myanmar. It is crucial to develop locally adapted high yielding hybrids to dramatically increase production. International Corn Foundation/Kyungpook National University (ICF/KNU) and Department of Agricultural Research (DAR) have developed a collaborative research to develop super hybrids. Under this program, 11 preliminary test cross trials including 538 crosses were tested in AungBan and NyaungMon (mid altitude) and Tatkone (lowland) Myanmar, and ICF Agric Center in Cambodia, 2008 rainy season. Test cross seeds were produced in Cambodia and Myanmar during 2007 winter season. Germplasms from Nepal, Myanmar, IITA, and CIMMYT were used. Simple estimates of commercial value score (1= best, 9= poorest) with yield potential, good agronomic traits and disease tolerance were rated. The analysis of variance for each trial showed highly significant among test crosses and better performance than local check hybrids. VN3 x SSA showed the highly tolerance to Northern Corn Leaf Blight in sticky corn trial. The outstanding performance was recognized in Nepal materials crossed with IITA materials. It is point out that overseas aids collaborative breeding and training of young staff are effective parts of Myanmar hybrid corn R&D program.

The common corn rust caused by Puccinia sorghi Schw. is widely distributed southern regions of temperate zones and sub-tropical regions world wide. It has been reduced corn yield significantly in Texas and Hawaii. The first author has observed incidence of this disease in Korea since ten years ago both in South (Kunwi, Ilsan, Pyungchang) and North Korea (Tongcheon). P. sorghi had very high infection in Jeju Island with over 2000 mm rainfall in 2008 on commercial hybrids from USA (DK 729, Pioneer 3394, P32P75) and Korea. All showed high susceptibility. Genetic tolerance could be the most economic way to control these fungi. The occurrence of this disease in Korea may be caused by environment changes. Pro-environment tolerance breeding with quantitatively inherited genes of host crop can guarantee for the durability and sustainability of crop cultivars under continuous changes of weather and environments.