CROP ESTIMATES AND PRICES
NOVEMBER CROP UPDATE
THE HUNT FOR THE CTV RESISTANCE GENE
RESERVOIRS
RUST MITES

CROP ESTIMATES AND PRICES -

I won't cover it again except to say that the Florida grapefruit crop estimate is way down with only 11 million boxes of whites and 4 million boxes of colored grapefruit projected after all the hurricane damages. That's about a third of last year's utilized production. Florida oranges are down about a quarter from last year's production.

Prices quotes were scarce, in part because of the delay in the startup of the season and possibly because shippers were hopeful to have a firmer idea of the losses in Florida. However, Texas shippers began to move fruit about the first of October-with early oranges being the hot item. Grapefruit movement through the first three weeks of shipping was only about a third of the volume as last season, navels are up about 16 percent and early oranges up a whopping 90 percent over the same time period.

Current prices for Texas Rio Star Fancy grade range from about $12 for 56's to $28 for 27's. Texas Rio Star Choice grade were quoted by US Market News Service at about $14 for size 48's to $26 for 27's. Early oranges are running $12 to $15, with no quotes on navels (though Florida navels are quoted from about $11 to $18).

Everyone knows, of course, that these kinds of prices will not last-but for a point of reference, Texas Fancy Rio Star ranged about $7 to $16 a carton at the same time last season, dropping to the neighborhood of $5 to $11 by the end of the holidays. At a comparable decline, 27's could still be pushing the $20 mark at the end of 2004.

Naturally, the f.o.b. price quotes have a major effect on grower returns, though it is sometimes difficult to establish a clear relationship. The relative mix of sizes and the packout confound most attempts to relate the two. It doesn't take a rocket scientist to figure out that the greater the proportion of Fancy grade and the greater the proportion of size 32 and larger, the greater the returns to the grower. Unfortunately, all of the crop can't be Fancy, nor can all of it be large, so Choice, PHE's, culls, and smaller fruit reduce grower returns to such low levels as to sometimes defy comprehension.

As a rule, culls and PHE's cost the grower money for pick and haul and for packinghouse costs, while Choice fruit is about a breakeven proposition. That means that no small part of the returns for Fancy fruit goes to offset the losses on PHE's and culls. As so well stated by Bob Smith in the last issue to the Texas Citrus Growers League Newsletter, most growers don't realize that they "pay" a significant amount of money to harvest and grade their packinghouse eliminations, as those costs are deducted from the proceeds before the check is issued. Lest you doubt it, there have been cases in which the packout and size mix were so low that the grower received a bill from the packinghouse rather than a check.

NOVEMBER CROP UPDATE -

Because of the hurricane damage in Florida and in response to industry concerns, the Florida Agricultural Statistics Service is assessing subsequent damage in terms of fruit size and fruit droppage that may have occurred since the October estimate was finalized. Consequently, the November 12 update of the citrus crop estimate for Florida may change to reflect the newer assessments-and that change could be either up or down, though most are probably betting that it would be lower.

THE HUNT FOR THE CTV RESISTANCE GENE -

A couple of months ago, Rod Santana wrote his weekly news column on the work of Dr. Erik Mirkov here at the Weslaco Center. Erik is a prominent researcher involved in genetic transformations of cane and citrus to impart either insect or disease resistance or both into those plants. He currently has a large number of nucellar Rio Red grapefruit trees that have been genetically modified for both pest resistance and citrus tristeza virus resistance. Because the trees are nucellar seedlings, they are still in a juvenile phase of growth, so they have not fruited as yet.

On another tack, Erik's lab has been breaking down the genome of Poncirus trifoliata to identify and isolate the gene that provides resistance to tristeza. As of the date of Rod's feature, Erik had narrowed the search to only 10 genes out of the thousands in the trifoliate genome-one of the 10 is the one he wants. Since that time, four of the 10 have been eliminated as the CTV resistance gene, while two of the remaining six are being assayed at the present time. His gut feeling is that one of the two that are in current assays is the CTV resistance gene-but assays of all will be completed by the first of the year whether this one is or isn't the right one.

What does this mean to citrus growers? One can only imagine. First and foremost will be the ability to transfer this single gene from trifoliate into commercially important citrus cultivars and rootstocks and thereby imbue them with resistance to tristeza. In other words, citrus growers in Texas can continue to grow on sour orange rootstock, while growers in other areas that have been ravaged by tristeza can return to sour orange stock or other stocks that are susceptible to tristeza.

Once Erik identifies the CTV resistance gene, work will begin to introduce it into citrus-but the resultant testing could take a few years. The prospect is tremendously exciting. The caveat, however, is that the resultant CTV resistant citrus will be what is commonly known as "genetically modified"-and there are a lot of people out there who are totally resistant to this concept. Some of those people are also opposed to agrichemicals, too.

The very beauty of gene transfers such as Erik is doing is that it enables the transfer of only those characters regulated by the gene or genes in question-and those characters are very specific. In other words, only the CTV resistance would be transferred, without the concurrent transfer of other, non-desirable, traits or attributes of trifoliate. The same result is theoretically achievable-but would take literally millions of controlled cross-pollinations and hybridizations, growing and testing of the progeny, and maybe-just maybe-one day in the next couple of millennia, the single CTV gene in trifoliate may appear in a seedling without all the other undesirable genes.

After this, maybe Erik will consider tackling the gene or genes that provide the well-known cold tolerance of trifoliate. Actually, he informs me that Dr. Elizar Louzada has cloned a gene from trifoliate that is "involved" in its cold hardiness.

RESERVOIRS -

As of mid-October, the U.S. share of waters in the two international reservoirs on the Rio Grande went above 80 percent of conservation level, while Mexico's share topped 60 percent. I still haven't taken the time to determine what the combined volume is in relation to conservation level-but it figures to be somewhere between the two percentages above.

RUST MITES -

They are still around and still causing problems. I talked with one grower who has had to spray twice in the last month-which suggests that something was amiss with the first application: my guess is either rain, too little material or application problems, as the chemicals used should have knocked them out and kept them out.

I'm beginning to wonder about the low gallonages we are using-as many of the control problems I hear about usually involves rates of 100 to 125 gallons per acre. As a rule, I rarely hear of problems from the 250-gallon rate. Call me dated if you will, but I remember rates of 1,000 or more gallons per acre in Florida when I worked there-and you can imagine my surprise when I came to the Valley some 25 years ago and learned that 500 gallons was the standard rate used here, with 250 gallons being quite common.

JULIAN W. SAULS, Ph.D.
Professor & Extension Horticulturist
2401 East Highway 83
Weslaco TX 78596