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A problem tomato growers might encounter are genetic defects in tomato seeds or seedlings that can prevent the plant from developing. While the origin of this problem remains unknown, there are steps you can take to address it.

The Problem

Ahern agronomists discovered this defect several years ago in in a large percentage of the “Tequila” variety tomato, which for many years was the market leader in the San Quintin Valley. Many of the seedlings didn’t grow after the cotyledon leaves, the first leaves produced, appeared. (See the first plant in the photo on the left.) With a tomato seedling in normal development, after the cotyledon leaves, the stem keeps growing and “true” leaves develop.

Some geneticists theorized that the defect occurred when the seeds formed in the tomato fruit. Others attributed it to unstable weather conditions or chemicals used on the plants. We placed our focus on how to keep the defective seedlings growing into productive plants.

If you notice that your tomato seedlings look like the ones in the photo, they will not produce fruit without your help. However, there is a method for getting tomato plants back on track.

One note: if your seedling looks like the first one on the left, with only two cotyledonal leaves and no growth point (the top end where the plant continually grows taller) forming, then there is no solution to this problem. These plants must be eliminated for quality control purposes.

The Solution

Rest assured, if your plant grows two true leaves after the cotyledon leaves, but still lacks a growing point, like the seedlings on the right in the photo, follow this process below. For this method to work, the seedlings must have had green cotyledon leaves.

  1.  Separate the seedlings that have true leaves, but no growing point, from the others developing normally.
  2. Give all the seedlings the same treatment (e.g., water, light, fertilizer).
  3. However, with the defective group, cut the stem 1 cm above where the cotyledon leaves grew.
  4. After one week, look for new growth from the stem. You should see the growth of apical meristems in the axils of the cotyledonal leaves.

This process can also be used on tomato seedlings in indeterminate varieties with normal development as long as the cotyledonal leaves were green, and the seedlings are otherwise healthy.