Increased size and weight of onion bulb ( Allium cepa L.) by nutrient translocation

Abstract

The onion ( Allium cepa L.) is the second most important food vegetable worldwide after the tomato and generates numerous jobs. Likewise, the average yield in Sinaloa is low relative to other parts of Mexico and the world. In this research we sought to know the increase of the size and weight of the white onion bulb, from the moment of folding of the leaf until its harvest. The variety “Carta Blanca” (Nunhems) was used that is of short days. A simple random sampling was performed on a surface of three hectares. Three measurements were taken, with an interval of one week between them. Measurements started when the blade was folded. To perform the statistical analysis, the normality of the data was verified and the homogeneity test was performed. The data were submitted to analysis of variance and mean Tukey comparison ( p < 0.05) with the SAS statistical package. A sensitivity analysis was also performed to estimate economic viability. The results show that at the beginning of leaf bending, the average diameter of the equatorial bulb was 7.48 cm, after one week the bulbs were 8.02 cm (diff erence of 0.53 cm). In the second week the diff erence with respect to the beginning of the folded sheet was 0.78 cm. In addition, during the third week the onion bulbs have stopped growing, at the same time the leaves lose their green color. This shows that the translocation continues even after having reached the physiological maturity of the plant which is manifested by folding the leaf. The sensitivity analysis indicates that if the onions were sold at 4 pesos and harvested one week after folding the leaf, the extra benefit would be $17 903.78 with an amount of 100 thousand plants per hectare and up to $71 615.13 with 400 thousand plants. In addition, two weeks after the doubling, the gains would be $26 363.18 and $105 452.70 respectively.