Evaluation of Four Sunflower Hybrids (Helianthus annuus) under Three Irrigation Regimes and Two Doses of Fertilization on Flower Production

Flower production is an income source for farming families. However, their productivity has been limited due to the lack of information on technical managements of crop species. In Mexico, 21,129 hectares are planted every year, with an annual production of 83,000 tons of flowers for decoration, and a total production value of 6,097 million Mexican pesos. In order to design agronomic management practices for sunflower production in the state of Campeche, three factors were evaluated- 1) sunflower hybrids, 2) time of irrigation and 3) fertilization doses, with four (hybrids- “Sunbright†, “Prado Red Shade†, “Full Sun†and “GH-382†), three (soil moisture tension at the start of irrigation of -10, -35 and -60 kPa), and two (Fertilization formulas- 60-50-0, and 30-25-0) levels, respectively using a sub split plot arrangement nested in a complete random block design with three replicates. Response variables evaluated were- plant height (PH), stem diameter (SD), leaf width (LW), leaf length (LL), distance between nodes (DN), number of inflorescences (NF), inner diameter (IDF), external diameter (EDF) and capitulum weight (CW). Irrigation affected PH, SD, LL, IDF, EDF, and CW. In all these variables, the highest values were found when irrigation was conducted at the lowest moisture tension (-10 kPa). Likewise, in all those variables significant effect of hybrids were found, which confirms that the morphology of flowers is defined by genetic factors. Specifically, hybrid “Full Sun†had significantly higher PH, SD, and DN compared to the rest of the hybrids. “Full Sun†and “Sunbright†had the highest values for PH and LL. “Full Sun†and “GH 382†had significantly higher IDF and EDF. “Prado Red Shade†had significantly lower PH, SD, LL, CW and higher NF. Fertilization only had significant effects on LW, DN and CW. In conclusion, irrigation improves morphological characteristics of sunflower plants. If the farmer’s objective is to produce larger flowers, then hybrids “Fun Sun†and “GH 382†are recommended. However, if the objective is to produce small flowers, hybrids “Sunbright†and “Prado Red Shade†are recommended. The latter is also suitable to produce a larger number of capitula.