Source- sink modulation in Chinese potato through agronomic management in the southern laterites of Kerala, India

Introduction

Tuber crops, considered as second most important food crops after cereals, are bestowed with climate resilient characters that enable it to perform under abiotic stress situations. Productivity in tuber crops is highly governed by canopy development, photosynthetic capacity and translocation of the photo assimilates to the roots, which forms the economic part. Chinese potato [Plectranthus rotundifolius (Poir.) Spreng.] is preferred for its short duration, nutritive and good energy value. Nevertheless, the crop is constrained by the higher proportion of miniature tubers, despite it being higher in number. Adoption of proper management strategies can favourably influence the size of tubers and result in higher yields.

Methods

The experiment was laid out in in split plot design with main plot treatments, m₁: bed method (30 cm x 15 cm), m₂: bed method (30 cm x 30 cm), m₃: ridge method (30 cm x 15 cm), m₄: ridge method (30 cm x 30 cm) and m₅: mound method (30 cm x 30 cm) and sub plot treatments, combinations of n₁: 60:30:120 kg NPK ha^-1 + PGPR Mix 1, n₂: 60:30:120 kg NPK ha^-1) and g₁: humic acid @@ 5 g L^-1, g₂: benzyl adenine @ 50 mg L^-1 and g₃: water spray) in four replications for two seasons.

Results

Pooled analysis revealed per hectare tuber yield and marketable tuber yield to be significantly the highest in bed method of planting with closer spacing of 30 cm x 15 cm (20.93 and 17.46 t ha^-1 respectively). Application of 60:30:120 kg NPK ha^-1 + PGPR Mix 1 + humic acid could result in 19.7 to 21.7 per cent increase in yields sole fertilizer application .

Conclusion

Resource management options of planting on beds at 30 cm x 15 cm and NPK application @ 60:30:120 kg ha^-1 along with PGPR Mix 1 and humic acid proved superior in enhancing the source strength and realizing higher yields. Per plant performance remained markedly better under wider spacing and per hectare yields in closer spacing.