An analysis of the effects of nutrient supply on the growth of potato crops

Fertilizer nitrogen did not delay tuber initiation by the potato variety King Edward in the field, but slowed the early growth of tubers. Later, N hastened tuber growth and the largest amounts prolonged it. Leaf and stem growth were increased by N from an early stage. Leaf area index (L) reached maxima of 2.5 to 3.0 with the largest amounts of N, and 1.0 with no nitrogen: L decreased after late July, faster with increased N, and only the largest amount prolonged the life of the haulm. N increased leaf area duration (D) by up to 125% in both years. D was 21% greater in 1964 than 1963, and net assimilation rate in August and September was larger; consequently mean yield was 50% more in 1964. Uptake of nitrogen and N % of dry matter were increased by increasing nitrogen. The N % of tuber dry weight remained constant or increased slightly from about 2 weeks after tuber formation, while N % of the leaves and stems decreased rapidly, and much N was transferred from tops to tubers. The 1964 results suggest that tuber growth depends on continued nitrogen uptake by the plant.

P and K had small effects compared with those of N. K increased leaf area duration by 9% in 1963 and 3% in 1964, and yield by 11 and 8% respectively. P increased leaf area duration by 17% and yield by 9% in 1964. K had very small effects until the end of the season, when it prolonged the period of growth. P increased growth rates of all parts of the plant up to 4 weeks from emergence, and the differences in dry weight at that time persisted to maturity but did not increase.[1]

The induction of second-growth in potato tubers

Experiments were carried out in glasshouses to induce second-growth in potato tubers under controlled conditions.

High temperature, irrespective of the water supply, induced second-growth in the tubers; drought did not induce or promote second-growth in these experiments. High temperature promoted the formation of new tubers of the first generation, and also branching and continued or renewed length growth of stolons and stems. High temperature temporarily returned the potato plant from a tuberizing stage into a more “vegetative” stage.[2]

An analysis of growth of the potato crop

Linear relationships between both total and tuber dry-matter yields and the amount of radiation intercepted by potato crops are demonstrated. Their existence suggests that, in the absenceof disease and drought, the essential objective in the production of this crop is to maximize radiation interception. This paper critically assesses the influence of factors which the grower can control on light interception and estimates potential yields for specific environments. The implications of this analysis for growers, breeders, research and the whole industry are discussed. [3]

Growth and Yield Components of Sweet Potato (Ipomoea batatas L.) and their Relationships with Root Yield

Aims: To assess the extent of the relationships of various growth and yield related characters. To evaluate the direct and indirect contributions of these characters to root yield, a basis of selection for further improvement.

Study Design: Field Experiment, in Randomized Complete Block Design.

Place and Duration of Study: Teaching and Research Farm of Bayero University, Kano (11°58’N and 8°25’E) and Agricultural Research Station Farm, Minjibir (12°11’N and 8°32’E) located in the Sudan Savanna of Nigeria between July-October, 2014.

Methodology: Sixteen (16) sweet potato advanced lines: Centennial, AYT/08/055, TIS8164, TIS87/0087, NRSP/12/097, UMUSPO/2, UMOSPO/1, SOLOMON1, EA/11/022, EA/11/025, EA/11/003, UM/11/015, NRSP/12/095, UM/11/001, UM/11/022, and a local check (Kantayi idda) were evaluated using a randomized complete block design with three replications. Data were collected on number of leaves per plant, vine length, vine weight, number of roots per plant, average root weight and the root yield. Simple and partial correlations between root yield (Y), growth and yield components (X) and within the growth and yield components themselves were worked out.

Results: Root yield was found to be significant (p<.01) and positively correlated with number of leaves per plant, number of roots per plant and average root weight. Vine length was negatively correlated to average root weight and root yield, whereas number of roots per plant was positively correlated to the average root weight and root yield. The path analysis also revealed that average root weight registered the highest direct contribution to root yield. The highest indirect effect on root yield also came from the number of roots per plant via the average root weight.

Conclusion: The average root weight contribution to root yield was much higher than those of vine length and vine weight both directly and indirectly. Thus, emphasis should be given towards increasing the average root weight and number of roots per plant as criteria and basis of selection of sweet potato for higher root yield.[4]

Influence of Main Stem Density on Irish Potato Growth and Yield: A Review

Our review confirms that stem density is affected by seed factors, seedbed conditions and planting methods. Physiologically old seed tubers develop into a ‘weak’ stem density. A loose friable soil that is warm and moist increases sprout emergence leading to a high stem number per hill. This high stem density can be achieved through the use of large seed tubers at planting. The greater the stem densities the higher the yield since more tubers are obtained per plant. An increase in inter stem competition associated with high stem desnity results in a decrease in harvestable tuber weight and size. However, our findings were inconclusive on the influence of varietal differences and planting depth on stem density. The influence of stem density on tuber specific gravity is also yet to be fully understood. We reiterate that producers for ware consumption should aim for low stem populations per hill while conventional seed producer are encouraged to take advantage of higher stem densities.[5]

Reference

[1] Dyson, P.W. and Watson, D.J., 1971. An analysis of the effects of nutrient supply on the growth of potato crops. Annals of Applied Biology, 69(1), pp.47-63.

[2] Bodlaender, K.B.A., Lugt, C. and Marinus, J., 1964. The induction of second-growth in potato tubers. European Potato Journal, 7(1), pp.57-71.

[3] Allen, E.J. and Scott, R.K., 1980. An analysis of growth of the potato crop. The Journal of Agricultural Science, 94(3), pp.583-606.

[4] Yahaya, S.U., Saad, A.M., Mohammed, S.G. and Afuafe, S.O., 2015. Growth and yield components of sweet potato (Ipomoea batatas L.) and their relationships with root yield. Journal of Experimental Agriculture International, pp.1-7.

[5] Shayanowako, A., Mangani, R., Mtaita, T. and Mazarura, U., 2015. Influence of main stem density on irish potato growth and yield: A review. Annual Research & Review in Biology, pp.229-237.