The effect of potato (Solanum tuberosum L.) minituber size on plant development and seed yield

The study was aimed to investigate the effect of planted potato minitubers size (weight) on some plant development characteristics (emergence, canopy closure) and yield parameters (tuber number and tuber yield of seed size grade 25 mm). The effect of cultivar was analysed as well. Three cultivars of different maturity (‘Monta’ – early maturity, ‘Prelma’ – medium early and ‘Mandaga’ – medium late maturity) were used. Minitubers of size ranges 3-5 g, 5-10 g, 10-20 g, 20 g were planted at field of State Priekuli Plant Breeding Institute, Latvia (57°31′ N, 25°34′ E) in 2014. Minitubers were pre-sprouted for two weeks before planting. Tubers were harvested by hand without prior haulm killing. ‘Monta’ was harvested 91 days after planting (DAP), ‘Prelma’ – 92 DAP, ‘Mandaga’ – 112 DAP. Statistically significant correlations (p is less than 0.05) were found between several plant development and yield parameters. Strong relationship was found between number of main stems mE-2 and progeny tuber number is greater than 25 mm per m2 (r = 0.714). The relationship between number of main stems mE-2 and tuber yield, kg mE-2, was moderate (r = 0.485). Canopy closure DAP correlated strongly negatively with the number of main stems mE-2 (r = -0.767) and progeny tuber number greater than 25 mm per m2 (r = -0.756). The relationship between canopy closure and tuber yield greater than 25 mm, kg mE-2 was moderately negative (r = -0.568). Progeny tuber number per m**2 had significant negative moderate correlation with DAP to 50%, 80% and between 50% and 80% emergence. However, no significant (p is greater than 0.05) relationship was found between tuber yield is greater than 25 mm, kg mE-2 and previously mentioned emergence parameters. Further repetitive experiments must be carried out to find more certain minituber size effects on various yield parameters, i.e. progeny tuber size distribution. As well, relationships between plant development data and yield parameters should be verified in further trials.