Citrus Research Report 2005
ABOUT THE COLLECTION
The Citrus Report, first published in 1978, is one of several commodity-based agricultural research reports published by the University of Arizona. The purpose of the report is to provide an annual research update to farmers, researchers, and those in the agricultural industry. The research is conducted by University of Arizona and USDA-ARS scientists.
Both historical and current Citrus Reports have been made available via the UA Campus Repository, as part of a collaboration between the College of Agriculture and Life Sciences and the University Libraries.
Contents for Citrus Research Report 2005Fertilization Practices
- Use of Plant Growth Regulators for Improving Lemon Fruit Size - 2005
- Nitrogen and Phosphorus Fertilizer Management for Young, Bearing Microsprinkler-Irrigated Citrus, Final Report
Nitrogen and Phosphorus Fertilizer Management for Young, Bearing Microsprinkler-Irrigated Citrus, Final ReportHigher nutrient and water use efficiency are possible with microsprinkler-irrigated citrus compared to flood-irrigated citrus. Therefore, new N and P fertilizer recommendations are needed for microsprinkler-irrigated citrus. The objectives of this project were to i) determine the effects of N applications of 0 - 0.8 lb/tree/yr on fruit yield, fruit and juice quality, and N and P removal in fruit for microsprinkler-irrigated navel oranges; ii) determine the effects of P applications of 0 - 0.2 lb/tree/yr on fruit yield, fruit and juice quality, and N and P removal in fruit, and iii) develop Best Management Practices for N and P fertigation of microsprinkler-irrigated citrus. Field experiments were conducted at the University of Arizona Citrus Agricultural Center in separate blocks of ‘Newhall’ and ‘Fukumoto’ navel oranges, both on ‘Carrizo’ rootstock. In each block, ten treatments, consisting of all possible combinations of 5 N rates (0, 0.2, 0.4, 0.6, and 0.8 lb N/tree/yr) and 2 P rates (0, 0.2 lb P/tree/year) were applied to five replicate trees per treatment. The maximum predicted yields for both varieties during all three seasons occurred at N rates of 0.4 to 0.55 lb N tree-1 yr-1. There were no significant effects of P application on fruit yield or quality. There were few significant effects of N or P fertilization on packout or fruit quality. The amounts of N removed in harvested fruit at the yield-maximizing N rates were equivalent to 50-84% of the N applied. New N fertilizer recommendations for microsprinkler-irrigated navel oranges are proposed.
Use of Plant Growth Regulators for Improving Lemon Fruit Size - 2005Lemons were treated with several plant growth regulators for the 2005-06 season, with the hope of improving fruit size. These PGR’s included CropSet, Accel, Maxim, Messenger and MT350. Although there were some increases in yield, these were just trends, and were not statistically significant. Similarly, there was no improvement in fruit size with application of the treatment
Mandarin Selection Trials in Arizona – 2005-06Second year yield and packout data from a trial containing ‘Fina’, ‘Fina Sodea’, ‘Sidi Aissa’, ‘Oroval’, ‘W. Murcott Afourer’, ‘Fremont’, and ‘Gold Nugget; selections were collected in 2004-05. For the year, ‘Fina Sodea’ had the greatest yield, and average fruit size, while ‘Fremont’ had the smallest yield, and the smallest fruit size.
Cultivar Selection Trials of Navel Orange in Arizona for 2005-06Two orange cultivar trials have been established in Arizona, one at the Yuma Mesa Agricultural Center, Yuma, AZ and one at the Citrus Agriculture Center, Waddell, AZ. For the navel orange trial in Yuma, all the selections had improved yields in 2005-06. ‘Fisher’ navel continues to have the greatest yield, but is quite granulated. Of the rest in the Yuma trial, ‘Lane Late’ had the best quality and yield. For the Waddell trial, the fourth year data has been collected, and suggests that ‘Fisher’, ‘Beck-Earli’, ‘Chislett’ and ‘Lane Late’ are outperforming the other cultivars tested to date.
Results of New Cultivar Selection Trials for Lemon in Arizona – 2005-06Three lemon cultivar selection trials are being conducted at the Yuma Mesa Agriculture Center in Somerton, AZ. Data from these trials suggest that ‘Limonero Fino 49’ selections may be a suitable alternative for the varieties most commonly planted in Southwest Arizona today. ‘Femminello’ and ‘Villafranca’ might also be planted on an experimental basis.
‘Lisbon’ Lemon Selection Trials in Arizona – 2005-06Four 'Lisbon' lemon selections, 'Frost Nucellar', 'Corona Foothills', 'Limoneira 8A' and 'Prior' were selected for evaluation on Citrus volkameriana rootstock. 2005-06 results indicate that the 'Limoneira 8A Lisbon' and ‘Corona Foothills Lisbon’ are superior to the other two selections tested.
Lemon Rootstock Trials in Arizona – 2005-06In a rootstock evaluation trial planted in 1993, five rootstocks, ‘Carrizo’ citrange, Citrus macrophylla, ‘Rough Lemon’, Swingle citrumelo and Citrus volkameriana were selected for evaluation using 'Limoneira 8A Lisbon' as the scion. 1994-2005 yield and packout results indicate that trees on C. macrophylla, C. volkameriana and ‘Rough Lemon’ are superior to those on other rootstocks in both growth and yield. C. macrophylla is no longer outperforming C. volkameriana. ‘Swingle’ and Carrizo’ are performing poorly.