"SNAP" [Simple Nutrient Addition Program Hydroponics] technique in screening rice for salinity tolerance at seedling stage

Salinity tolerance in rice is a very important trait for increasing rice productivity in saline areas. Breeding for salinity tolerance requires reliable screening technique. The screening technique developed at IRRI uses a nutrient solution adapted from Yoshida et al. (1976) which provides rapid screening of large number of materials and reproducible results. However, this technique is very expensive and the preparation and maintenance of the nutrient solution are labor intensive. SNAP or the Simple Nutrient Addition Program Hydroponics developed by the Institute of Plant Breeding, UPLB [University of the Philippines] was evaluated as an alternative for use in screening rice for salinity tolerance at seedling stage. SNAP solution was compared with the nutrient solution in terms of its preparation, costs, maintenance, and ability to sustain growth of rice plants for the whole screening duration. SNAP hydroponics require only two stock solutions while the present nutrient solution requires six stock solutions. SNAP solution costs only PhP 1.00 per liter while nutrient solution costs about PhP 6.68 per liter. Furthermore, a one time preparation of SNAP solution is enough for the whole screening duration, while weekly renewal is necessary for the nutrient solution. Nutrient solution requires distilled water while SNAP solution can use tap water in its preparation. Nutrient solution requires daily adjustment of pH while for the SNAP solution it can be monitored and adjusted weekly as long as it falls within the acceptable range. Thus, it is more tedious to maintain the nutrient solution than SNAP solution. Both solutions sustain normal growth of rice plants and are equally effective in salinity tolerance screening. Salinized SNAP solution was found to be extremely cost effective (6 times cheaper) and labor saving (50%) than the nutrient solution technique in screening rice for salinity tolerance at seedling stage. With this new low-cost screening technique, breeding can be less costly and can be readily available to national agricultural research institutions.