In 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.

Three 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.

Second 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.

Four '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.

Two 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.

The influence of 12 different rootstocks on yield and quality of "Redblush" grapefruit was studied for several years. Rootstocks consisted of: macrophylla, volkameriana, rough lemon, Palestine sweet lime, sour orange, Carrizo citrange, taiwanica, Savage citrange, Citrumelo, Ichang pummelo, Troyer citrange and Cleopatra mandarin. Trees on volkameriana, Palestine sweet lime, rough lemon, and sour orange had higher yield than other rootstocks, while trees on Savage citrange had lowest yield. However, soluble solids and acid /sugar ratio were relatively low in the fruits on volkameriana but high in fruit on Savage citrange rootstocks.

In 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. 1994-2006 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 does not consistently outperform C. volkameriana. 'Swingle' and Carrizo’ are performing poorly.

Four 'Lisbon' lemon selections, 'Frost Nucellar', 'Corona Foothills', 'Limoneira 8A' and 'Prior' were selected for evaluation on Citrus volkameriana rootstock. Yield was extremely low for 2006-07, but these results do not change the fact that that 'Limoneira 8A Lisbon' and 'Corona Foothills Lisbon' are superior to the other two selections tested.

Three 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' and 'Cascade Eureka' 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

First 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, 'Fremont' had the greatest yield, but the smallest fruit size, while 'Fina' had the smallest yield, and 'W. Murcott Afourer' had the largest fruit size.