The effect of ratooning and application of nitrogen and potassium fertilizers to total of soluble proteins in the leaves of M 442-51 and PS 60 cane varieties

Suyoto Hadisaputro
(Indonesian Sugar Research Institute Jl.Pahlawan 25 Pasuruan 67126)

ABSTRACT

Ratooning system has been implemented in all cane fields, but the system can reduce productivity and growth performance of cane. One factor that affects the cane growth performance is enzyme activities, and its activities are in general can be indentified as total of soluble proteins. This experiment was done to study the effect of ratooning and application of nitrogen (N) and potassium (K) fertilizers to the total of soluble proteins in the leaves of M 442-51 (cane variety with good ratooning ability) and PS 60 (cane variety with bad ratooning ability). The experiment was conducted at the Indonesian Sugar Research Institute (ISRI) Pasuruan, East Java. The results showed that the totals of soluble proteins in cane leaves were influenced by genetic and environmental factors. There was found that ratooning system reduced the total of soluble proteins, but it depended on the cane variety. The reduce of the total of soluble protein on M 442-51 was higher than that of PS 60. Meanwhile, it was found that by increasing the dosage of both N and K fertilizers, the total soluble proteins in cane leaves can increase, but there were different responses between two cane varieties observed. M 442-21 had a better response to N dosage application than PS 60, and conversely PS 60 had a better response to K dosage application than M 442-51. Moreover, it was also found that improvement of the total of soluble proteins as a result of increasing K fertilizer dosage application on sugarcane with N deficiency was higher than that of sugarcane with enough N. Similarly, improvement of the total of soluble proteins as a result of increasing N fertilizer dosage application on sugarcane with lack of K nutrient was better than that of sugarcane with enough K. Anyway, the rate of improvement of the total of soluble proteins caused by N and K fertilizers was not an addition model but it was a resultant model as the effect of each nutrient studied.
Key words: sugarcane, M 442-51, PS 60, ratooning ability, nitrogen, potassium, total of soluble proteins