BAR TODAY || Official Quarterly Publication of the Bureau of Agricultural Research

USM develops new corn varieties
by Likha C. Cuevas

July-September 2003
Volume 5 No. 3

Two new higher-yieldingcorn varieties with moderate resistance to downy mildew (Peronosclerospora philippinensis) and corn borer (Ostrinia furnacalis) are now available in the market. The University of Southern Mindanao (USM) in collaboration with Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT) developed USM Var 9 and USM Var 14 which the National Seed Industry Council (NSIC) has already approved for commercial release.

Corn is considered as the one of the most important crops (only second to rice) in the Philippines. However, corn production in the country has been declining over the years due to massive land conversion and shifting to other crops by farmers. Since 1993, the area harvested to corn continued to decline, with only an average of 2.63 million hectares from 1995 to 2000. Problems with pests and diseases also add strain to corn yield.

According to studies, the Asian corn borer infestation was observed to occur yearly in study sites and it has been increasing during the last 10 years. On the other hand, downy mildew was observed to be decreasing in some areas but in Cotabato, disease incidence is increasing. Losses due to downy mildew were recorded to be as high as 40%. El Niño also accounted for the drop in corn production, especially in 1998.

Though production is low, the demand is great as corn is used for feed formulations (60% of the total corn requirement) and human consumption, particularly in the Visayas region. It is also processed into starch crystalline sugar (dextrose), corn syrup, and refined corn oil. To augment the needed amount, the country has to import commercial corn grains, which makes the crop more expensive. To boost domestic corn production, efforts were put into genetic resource conservation, pre-breeding, population improvement, development of special trait materials (like disease resistance), and open-pollinated varieties (OPVs) development. Farmers are encouraged to plant high-yielding new varieties like the OPVs instead of the low-yielding native ones.

This need for new varieties led to the development of USM Var 9 and USM Var 14 at the USM Agricultural Research Center (USMARC) in Kabacan, Cotabato. According to USM researchers led by F.R. Alejandro, USM Var 9 and USM Var 14 are superior to the commercially available varieties. These varieties are what the Filipino corn farmers need.

The fist step in the study was germplasm (breeding stock) collection and evaluation. The researchers gathered corn materials from CIMMYT and other private and public institutions, including USM varieties, and these were screened to see which of these were potential sources of good breeding lines. Later, experimental varieties that resulted from random cross breeding were screened for downy mildew and corn borer resistance. The plants were tested for their grain yield and the CIMMYT formula was used in the computation of the total grain yield.

USM Var 9 was first coded as USMARC 99149 (with grain yield 6.10 t/ha) and was submitted to the National Cooperative Testing (NCT). At NCT, the variety yielded 5.63 t/ha, which was 1.8% higher than the national check USM Var 5 (5.53% t/ha). It yielded more than the check by 5.60% in Visayas and 5.50% in Mindanao and this made the variety qualify for regional commercial release. The NSIC later approved USMARC 99149 as a commercial variety for Visayas and Mindanao in 2001.

USM Var 14 with grain yield 6.20 t/ha, was first coded as USMARC 9902 upon submission to NCT. This variety yielded 4.78 t/ha in NCT, which was 1.05% better than the check USM Var 10/USM Var 8. It also yielded more than USM Var 10 and USM Var 8 by 4.42% in Luzon and by 6.59% in Mindanao. The results made USMARC 9902 for regional release in Luzon and Mindanao and was named USM Var 14 after NSIC approval.

References:
Alejandro, F.R., Cena, R.L., Tangonan, N.G., Maarat, C.A., Solilap, E.L., and Escalante, W.B. USM Var 9 and USM Var 14: New Open-Pollinated Varieties of Corn. USM R&D J 10(1):1-10 (2002)
Gonzales, L.A. The Philippine Corn Indusrty Global Transition: Some Strategic Issues and Policy Directions. Proceedings of the 1st Annual Philippine Corn Symposium and Planning Workshop (1): 9-36 (2003).
Gerpacio, R.V. Setting Priorities for the Philippine Maize RD&E System An Application of the CIMMYT Methodology. Proceedings of the 1st Annual Philippine Corn Symposium and Planning Workshop (1): 9-36 (2003).