Irrigation strategies of sugarcane seedlings from micropropagation and biofactory methods

The sugarcane industry has been suffering from unstable productivity on commercial fields. The major factors causing this problem are mechanized harvesting damage to cane clumps in the field and the slow process of releasing and adopting new sugarcane cultivars. By utilizing new micropropagation processes involving the extraction of apical meristem from new cultivars and biofactory methods for multiplying the material, it is possible to produce an extraordinary number of sugarcane seedlings to provide nurseries rapidly with new cultivars for planting on commercial fields. The goal of this study was to evaluate several irrigation strategies (IS) to determine the best one for supplying the biofactory sugarcane seedlings water requirements, under conditions of different volumes of substrate (VS): 56, 73, 93 and 125 cm³. The irrigation management experiment comprised eight IS based on different periods of accumulated reference evapotranspiration (ETo). We found that the irrigation application must occur at intervals below 30 mm of accumulated ETo. IS1 (maintenance of soil moisture at field capacity) results in a larger number of tillers, longer extension of the primary stalks, and enhanced dry matter (DM) yield independent of VS. The VS factor accounted for statistical differences in sugarcane survival rate and morphological characteristics, but only for low initial soil moisture conditions. The intermediate VS of 73 cm3 was the best option for plants to thrive in the field; larger VS (93 and 125 cm3) produced young plants with many leaves, which transpire a lot in the field, increasing the chances of early death under water stress after planting; the smaller VS (56 cm3) resulted in young plants with small root systems and minimal water reservoirs, resulting in lower survival under drought conditions.