Effects of cultivars and chemical fertilizer rate on growth fresh root yield and root starch content of cassava | เธœเธฅเธ‚เธญเธ‡เธžเธฑเธ™เธ˜เธธเนŒเนเธฅเธฐเธญเธฑเธ•เธฃเธฒเธ›เธธเน‹เธขเน€เธ„เธกเธตเธ—เธตเนˆเธกเธตเธ•เนˆเธญเธเธฒเธฃเน€เธˆเธฃเธดเธเน€เธ•เธดเธšเน‚เธ•เธœเธฅเธœเธฅเธดเธ•เธซเธฑเธงเธชเธ”เนเธฅเธฐเธ›เธฃเธดเธกเธฒเธ“เนเธ›เน‰เธ‡เนƒเธ™เธซเธฑเธงเธกเธฑเธ™เธชเธณเธ›เธฐเธซเธฅเธฑเธ‡

Effects of cultivars and chemical fertilizer rate on growth fresh root yield and root starch content of cassava were studied. The experiments were conducted using a split-plot design in RCB with 4 replications at the Tapioca Research and Development Center (TRDC), Tambon Huay Bong, DanKhuntoad District, Nakhon Ratchasima Province. The main plot were 4 varieties of cassava Kasetsart 50 Rayong 72 Huay Bong 60 and Hybrid MKUC34-114-106. planted in June 26, 2003-2004. The 5 sub-plots were identical. They were: Chemical Fertilizer formula 15-7-18 at the rate 0 (control), 25 50 75 and100 kg/rai. The result of treatments is statistically significant affect cassava for top weight all where Huay Bong 60 difference from Hybrid MKUC 34-114-106 and Rayong 72 ,similar with Kasetsart 50 difference from Rayong 72. The results of all treatments did not statistically significant affect cassava root yield, the result was also observed Hybrid MKUC 34-114-106 they tended to increase cassava root yield 6,401kg/rai when compared with 4 cassava variety. The results revealed that root starch content all treatments is statistically significantly. The root starch content in Hybrid MKUC 34-114-106 Kasetsart 50 and Huay Bong 60( 25.6 percent 25.2 percent and 25.3 percent) are difference from Rayong 72 (23.3 percent). The control plots and input chemical fertilizer formula 15-7-18 at the rate of 25 kg/rai where cassava root starch content was the increase 26.3 percent and 25.4 percent and found that input chemical fertilizer formula 15-7-18 at the rate of 50 75 and 100 kg/rai the results revealed that root starch content lowest average 24.9 percent 23.9 percent and 23.6 percent. The harvest index of Rayong 72 was greater (0.56) The result treatments control and input Chemical Fertilizer at the rate of 50 kg/rai increase average 0.54 and 0.53 but statistically significant treatments found that input Chemical Fertilizer at the rate of 25 75 100 kg/rai the results revealed that lowest average 0.51 0.51 and 0.49. The yield root dry matter in all treatments did not statistically significant. The average of yield root dry matter in 4 cassava varieties is 2,111 kg/rai.