THIRUVANANTHAPURAM: In what could be a major turning point in the rubber production in the country, the Rubber Research Institute of India (RRII) will release two new high-yielding rubber clones for commercial cultivation on October 6. These new varieties, RRII 417 and RRII 422 clones will be dedicated to the nation by Union Commerce Minister Anand Sharma at Puthuppally, Kottayam.
What is significant about the two new varieties is that they are found to show superior yield in comparison to the highly popular clone RRII 105, which had a tremendous impact on the improvement of rubber productivity in the country. The new clones are also expected to positively influence the value of Indian rubber in the world market.
The mean dry rubber yields of new clones are both above the yield from RRII 105, considered to be one of the best and high yielding clones. Both in small-scale trial and large-scale trial, the new clones surpassed RRII 105.
While in small-scale trial RRII 417 showed better results, in large scale trial, both RRII 417 and RRII 422 fared the same.
‘’It took us 26 long years to develop these clones. The multi-location trials within Kerala also took a long time’’ said RRII Kottayam director Dr James Jacob. ‘’Both the new clones have higher latex and timber production than RRII 105,’’ he added.
The growth pattern of RRII 417 was vigorous with more number of trees coming to tapping by seven years than RRII 105. The new clones, RRII 417 and RRII 422 are superior to RRII 105 in terms of growth and productivity.
Having performed well in various locations, these two clones have been upgraded to Category-I of the planting recommendations of the Rubber Board, which means that from experimental planting, it is now recommended for large-scale planting.
Currently, six clones are recommended by the Rubber Board for large-scale cultivation in India, out of which five are developed by Rubber Research Institute of India. They are RRII 105, RRII 414, RRII 430, RRII 417, RRII 422 and PB 260 facilitating multi-clone planting by rubber growers.
While the disease reaction of these clones are comparable to that of RRII 105, the Rubber Board recommends preventive measures against major diseases.
RRII 417 is moderately tolerant to pink disease and corynespora leaf disease but incidence of powdery mildew is high. Incidence of abnormal leaf fall in RRII 422 is moderate to high and pink disease is low. Powdery mildew is moderate to high and corynespora leaf disease is high.
The mean yield of RRII 417 over 11 years of tapping in small-scale trial was 71 g/tree/tap and in large-scale trials over seven years of tapping was 69 g/tree/tap. The corresponding yield of RRII 105 was 53 g/tree/tap.
RRII 422 clone recorded 65 g/tree/tap in the small-scale trial over 11 years of tapping and 69 g/tree/tap in the large-scale trial over seven years of tapping. The corresponding yields of RRII 105 were 53 and 56 g/tree/tap respectively.
What is even more interesting is that these two clones are said to be promising in non-traditional rubber cultivating areas, including North-East India. Early tappability along with high yield is a highly desirable feature of RRII 417 and RRII 422.
Scientists of RRII were working on the production of high yielding varieties with parentage RRII 105 x RRIC 100. Of the most recently evolved RRII 400 series clones, clones RRII 414 and RRII 430 were released in July 2005.