I. AGRICULTURAL RESEARCH & DEVELOPMENT
A. LUZON AGRICULTURAL RESEARCH & EXTENSION CENTER (LAREC)
1) Free-Proline Accumulation for Drought Tolerance of Sugarcane Varieties
The drought tolerance of the sugarcane high yielding varieties (HYVs) were evaluated based on free-proline accumulation. Low soil moisture condition increased free-proline accumulation in sugarcane plants. The 30-day moisture stress duration when the sugarcane plants were 5 months old, was the critical sampling period for free-proline analysis. Phil 8013, Phil 90-1237, Phil 92-0051 and Phil 91-1091 accumulated significantly higher free proline than the other test varieties. Varieties with high free-proline accumulation produced high cane tonnage and sugar yields.
2) Varietal Response of Sugarcane to Distillery Effluent
Ten commercial varieties were tested for growth and yield response to raw distillery effluent. In general, the ten varieties gave comparable response in terms of growth and yield in both the 100 tons effluent/ha and N fertilizer treatments in both the plant and ratoon canes. None of the varieties exhibited phytotoxic effects to effluent application.
3) Influence of Season of Planting on Incidence of Sugarcane Downy Mildew caused by Peronosclerospora philippinensis (Weston) C. G. Shaw
The study determined the incidence of downy mildew infection when planted in October (Early season planting), December (Mid-season planting) and February (Late season planting). Percent downy mildew infection was highest in October planting, followed by February planting and December planting with the lowest infection. While the differences in percent infection was insignificant, percent infection significantly influenced the number of tillers, stalks height and cane and sugar yields.
4) Occurrence and Control of Parasitic Nematodes Attacking Sugarcane
Eight nematode genera were identified in the soil samples collected from four mill districts: Balayan (Batangas), Don Pedro (Nasugbu), Pampanga, Tarlac (San Miguel) and LAREC (Floridablanca, Pampanga). The most predominant genera observed were Pratylenchus, Tylenchorhychus, Helitocylenchus, Croconemella and Rotylenchus. The other nematodes found but fewer in number and lesser in distribution were Hemicycliophora, Hoplolaimus and Xiphenema. Sugarcane plants inoculated with more Pratylenchus population multiplied and increased as the sugarcane plants developed more roots. The uninoculated sugarcane plants had better green leaf weight, stalk length and weight and basal diameter than those infected with nematodes. Plants inoculated with few Pratylenchus populations had heavier green leaves and longer and bigger stalks than those with more nematode populations. Starguard D100, Cadusafos and Carbofuran significantly controlled the nematode populations. One to 5 months after treatment, Starguard D100 effectively reduced the nematode populations better than Cadusafos and Carbofuran. The effectiveness of the test nematicides declined with growth of sugarcane but their nematodes populations remained lower than those of the of the untreated plots. The results indicate the pathogenic effects of parasitic nematodes to sugarcane as shown in the reduction of stalk length and weight, basal diameter, number of tillers and cane and sugar yield. Sugarcane treatment with nematicides had better cane and sugar yield than those without treatment.
5) Productivity Improvement of Soil Planted to Sugarcane with Liquid Sewage Sludge