1. Assessment of Sugarcane Maturity for Optimum Sugar Yield Khin Myint Kywe

2. Despite a high tonnage of millable sugarcane the highest possible sugar yield is still dependent on the degree of maturity of cane plant at harvest time. Hence it is essential to harvest the cane at peak maturity. Preharvest maturity testing could indicate the exact time to harvest. Introduction

3. Sugarcane is considered to be mature or ripe when the sucrose accumulation in the bottom and top portion of cane stalk is about equal. The ratio of the brix (soluble solids in cane juice) of the top third of the stalk to the brix of the bottom third approaches unity or nearly unity when the cane is ripe. This method is simple, rapid, and inexpensive and still in wide use today.

4. Refractometer for testing sugar content

5. Maturity testing by Physiological Changes Brix determination using a hand refractometer is the most reliable method of monitoring maturity in the field. Brix is the percent solids in the cane juice which roughtly estimates sweetness in cane. Maturity is indicated by a more or less uniform and high brix reading of the juice collected from the top, middle and basal portions of the stalk. An immature stalk has high brix reading at the base and low at the middle and top. The overmature cane registers high brix at the top and low at bottom

6. To determine the optimum time of harvest for four sugarcane varieties To minimize post harvest sugar losses at fields/ cane centers /mill yard.

7. Materials and Methods  This study was conducted at the Pyinmana Sugarcane Research Center,Sugarcane Development Department, Pyinmana, NayPyitaw, during October, 2010 to January 2011.  4 sugarcane varieties were planted on 15 th January 2010 in rows keeping one meter distance between row to row and one feet distance from set to set.  Maturity test by using refractometer started from 15 th October 2010 to 30 th January 2011  Sampled cane of each test variety were selected and brix reading of the juice collected from the top, middle and basal portions of the stalk were recorded.

8. Procedure of Maturity Testing 3 millable stalk samples Weighted Counting the internode Number Divided three equal parts Crushed separately by 3 roller laboratory mill Analyzed for brix of each part by hand refractometer Calibrated with brix hydrometer

9. Maturity Test results of four sugarcane Varieties Sr. Record Date Kps-94/13K-88/92K-95/84K-95/283 TMBTMBTMBTMB 115.10.201016.018.518.914.516.518.513.015.517.515.017.018.5 230.10.201016.319.020.015.018.019.013.517.018.015.017.919.1 315.11.201017.120.320.816.621.021.514.617.718.117.421.021.5 430.11.201020.8 20.917.518.519.7518.019.520.518.521.021.7 515.12.20102120.520.920.021.221.419.3921.221.420.521.521.8 631.12.201021.520.020.321.021.321.521.021.321.5 21.721.9 715.1.201120.019.5 21.521.721.922.021.521.9 21.521.7 831.1.201119.518.519.022.021.021.522.021.621.722.021.7

10. Maturity Results of Different Sugarcane Varieties Sr.NameMaturity Time of varieties 1Kps-94/13End of November 2K-88/92Middle of December 3K-95/84Middle of December 4K-95/283Middle of December

11. Maturity Test results of Kps-94/13

12. Environmental conditions during studied period MonthTemperature(˚C)Rainfall MaxMin(mm) October,201033.3623.96210 November,201034.6020.30- December, 201031.6016.1216 January,201130.7714.4450  During the period of maturity testing program rainfall was abundant on October, 2010 & continued to January, 2011.  The differences between maximum and minimum temperature were about 10 to 16 October to January

13. 1. Harvesting is one of the critical operations in sugarcane farming and untimely harvesting results in the loss of tonnage and sucrose content. 2. The ripening of sugarcane or actual accumulation of sugar starts from the months of October to November. 3. Sugarcane crushing season in Myanmar starts between mid November to end January. Constraints and lessons learnt during implementation

14. 4. Maturity testing of sugarcane varieties, therefore, used to start mid October. 5. Although a perfect maturity state is theoretically attainable, in actual practice, deviation from a nice fit of peak maturity point may be expected due to unfavorable weather conditions and sampling variation.

15. 1. Sugar yield reduction from early & late season harvest could be minimized by scheduling cane harvest in order of degree of maturity & juice quality. 2. Rapid & accurate method of maturity testing is essential to determine the harvest time for maximum sugar production. 3. Fully mature cane will not deteriorate as rapidly as either immature or over mature cane. Recommendations

16. 4. Present study was the evaluation of maturity of four cane varieties, other promising varieties need further testing. 5. To obtain the highest possible yield from sugarcane, the crop should be harvested when mature. 6. The peak sugar recovery was usually achieved in mid- December.