Tomatillo: Evaluation of a Potential New Ethnic Vegetable Crop for Indiana

Mario R. Morales Department of Horticulture and LA Purdue University West Lafayette, Indiana 47907

Introduction

Tomatillo, also known as tomate verde (green tomato), tomate de cáscara (husk tomato) and miltomate, is an herbaceous, indeterminate, sprawling, annual plant native to Mexico and Guatemala. It is a relative of tomato, eggplant, pepper, potato and tobacco and belongs to the Solanaceae family. Tomatillo has a tart flavor, some say similar to green apples, others say similar to tangy lemons. Mexicans use it in many ways. Cooked, it provides a distinctive flavor to stews, moles and sauces for tacos, tamales and enchiladas. Fresh, it adds a special flavor to salads, appetizers and sandwiches. It is used cooked or fresh to prepare the popular green sauce (salsa verde). The tomatillo fruit grows faster that the husk that covers it, breaking it open as it reaches full size. For the best quality and flavor, tomatillos need to be harvested at full size, when the husk has just turned tan but the fruit is still green. Depending on the cultivar, when the fruit ripens it can turn light green, yellow or purple, and it will get sweet losing its tangy flavor.

In Mexico, where tomatillo is almost as popular as regular tomato, the area planted with this vegetable in 2000 was 125,732 acres with a yield of 5.2 tons/A. In California, on the other hand, with a population of 2 million Hispanics, mainly of Mexican origin, the area planted in 1997 was only 161 acres with very low yields (1.9 tons/A), but the gross value/acre was good ($5,134). There is currently very little commercial tomatillo production in the United States. Tomatillos are generally imported from Mexico packed in wooden crates for sale in grocery stores.

The Indiana Hispanic population grew 117 % during the last 10 years, from 98,788 in 1990 to 214,536 in 2000. There are now close to _ of a million Hispanics living in Indiana of which 71 % (153,042) are of Mexican descent. The Hispanic population usually consumes vegetables native to their place of origin, which are imported from abroad. There is here a good size market that is not being fully exploited. Very few Indiana growers produce Hispanic vegetables. Local production of these vegetables would reduce costs and benefit dozens of producers. If the number of growers interested in Hispanic vegetables increases, there will be need to determine which commercial varieties are the best for Indiana environmental conditions. This paper reports on the evaluation of seven tomatillo commercial cultivars in central Indiana.

Materials and Methods

Seven tomatillo commercial cultivars were seeded in the greenhouse at Purdue University, West Lafayette, Indiana on April 29, 2001. Plants were grown in 72-cell plastic trays and transplanted into a randomized complete block design with three replications on June 6. Field preparation on May 30 included the preplant incorporation of 1pint/acre of Treflan and 100 Lb/acre of urea. The trial was planted on raised beds covered with black plastic mulch for weed control. Trickle irrigation lines were placed beneath the plastic mulch to provide water to the growing plants as needed. Beds were 7 feet apart from center to center. Plots had one row with plants spaced 2’ apart. The trial was sprayed with Pounce 3.2EC for fruit worm control on August 1. Tomatillo is an indeterminate plant and keeps producing fruit as the season progresses. Plots were harvested several times during the season. The first harvest was done on August 3 and the last on October 4. Data were processed using SAS, a software system for data analysis.

Results and Discussion

Tomatillo plants grew vigorously in Indiana and did not present any serious disease or insect damage during the vegetative stage. All varieties had an indeterminate growth that became prostrate as the branches grew larger and developing fruit started to put weight on them. As branches kept growing and sprawling, plants became tangled making harvest difficult and laborious. Yields were affected by a strong hail-storm on August 18 that lodged plants, broke branches and damaged fruit. Artificial infestations for Entomological studies usually keep populations of fruit worms high at the farm. Late in the season, these insects affected yield performance even further by causing fruits to rotten and drop before reaching full size. However, tomatillo is a very productive plant and yields were still well within an acceptable range. Supertillo, a new cultivar, had the highest yield (21.6 tons/A), the second highest number of fruits per plant (284) and a large average fruit weight. Supertillo had also the shortest plant height (19”) and a more open canopy that facilitated harvest. Verde Puebla was the second best variety with a yield of 18.9 tons/A and the largest average fruit weight (0.9 oz). The number of fruits per plant of Verde Puebla was below average, but this was compensated with large size fruits, a characteristic that most growers and consumers like. Rendidora is a cultivar developed by mass selection in Morelos, Mexico in the 1980’s. It is still a good cultivar with yields above average (17.9 tons/A) and fruit of acceptable size. Days to flower were about the same in all the cultivars evaluated.

Table 1. Yield characteristics of tomatillo cultivars grown in central Indiana, 2001

Number of Ave fruit Seed Days to Plant height Yield. fruits per weight Cultivar Source flower inches tons/A plant oz

Supertillo CN 59 19 c1 21.6 a 284 ab 0.79 ab Verde Puebla CN 58 25 bc 18.9 ab 228 bc 0.90 a Rendidora RT 55 20 c 17.9 abc 237 bc 0.79 ab Toma Verde JS 60 30 ab 15.4 bc 234 bc 0.69 bc Purple JS 59 34 a 15.1 bc 246 bc 0.63 c De Milpa JS 58 31 ab 12.6 c 358 a 0.37 d Tomatillo SW 54 29 ab 12.4 c 161 c 0.81 ab

Mean 58 27 16.3 250 0.71 C.V. 16 18.0 20 11.8 R2 0.74 0.72 0.75 0.88

1 Means spanned by the same letter are not significantly different.