Effect of Drought Stress on Initial Growth of Five Sugarcane Clones in Peat Media

Sugarcane is a plant that has the potential to be cultivated in West Kalimantan to fulfill sugar needs. In 2018, the average sugarcane production in Kalimantan was 410 kg/ha/year. This means that sugarcane has the potential to be developed in West Kalimantan as support for the government to achieve sugar self-sufficiency in 2024. According to [1] the Kalimantan area is one of the suitable areas for sugarcane production by taking into account the water deficit and harvest time. Efforts to increase sugarcane development can be carried out on sub-optimal landon peatlands with the application of appropriate technology and processing systems [2]. However, drought conditions often occur when entering the dry season due to increasingly limited water supply and climatic anomalies that result in a longer dry season, as a result, plants are stressed in conditions of water shortages so that they cannot grow and develop optimally. Even though the availability of adaptive clones on sub-optimal land is still limited and becomes a problem in the development of sugarcane on peatlands. Drought stress is a limiting factor in the early growth phase of tiller formation [3]. In the vegetative phase, lack of water causes a decrease in the number of tillers, stem elongation which ends in a decrease in sugar yield because in the vegetative phase there is a process of cell division, cell elongation, and the initial stage of cell differentiation which will develop stems, leaves and root systems which will later be used for produce sugar yield.

One strategy to solve the problem of drought is by planting sugarcane clones tolerant of drought stress through growth indicators for several sugarcane clones that have the potential to be cultivated on peatlands. The use of drought tolerant clones is more profitable in the long term. Plants can grow in conditions of stress by adapting to develop their morphological and physiological processes. [4] Resulted plants experiencing drought conditions will survive by reducing CO assimilation 2 by 66% and their transpiration through stomata closure and will increase or recover after irrigation. One of the drought tolerance of sugarcane clones is determined based on its growth. Research conducted by [5] using five sugarcane clones resulted that the PS881 clone and PS864 clone regression test resulted in a regression coefficient of less than one, which means that both clones can adapt to a less than optimal environment. PS881 clone planted on dry land vertisol soil with a spacing of 30 cm x 100 cm with single bud planting material produced the best productivity [6]. [7] Showed that the initial growth of sugarcane plants can run optimally if the water capacity in the soil is at least 50% and at least 80% in the stem elongation phase. If the soil water content decreases to 40% (suboptimal) it can reduce 50% of the number of tillers formed at 2-4 BST and at 100% optimal soil water content or in a state of field capacity the number of tillers increases from 5.04 tillers/polybag to 7 ,33 tillers/ polybag.

The purpose of this study was to determine the effect and interaction of water availability in media and sugarcane clones on early growth of sugarcane on peat media and clones that are resistant to drought stress in peat media based on growth indicators. Research on the resistance of sugarcane clones to drought stress through growth indicators can be used as a basis for starting sugarcane cultivation on peatlands during the dry season and developing further research.