Rutgers bell pepper bacterial leaf spot trial, 2021

Evaluate bell pepper cultivars for bacterial leaf spot under natural infection in a state where all eleven races of the pathogen are known to occur, and record fruit characters from the same plots.

Production system. field.

Analysis. Symptoms were rated on the report’s own nought to four scale, where higher is worse, and the scale is descriptive rather than an equal-interval measure. Infection was natural rather than inoculated, so this records how each cultivar met whatever races were present in that field.

Bacterial leaf spot symptom rating, 0 to 4. A single visual rating taken after the last harvest, on the report’s own scale: 0 no symptom development; 1 few leaf spots, strong plant growth and canopy; 2 major leaf spotting and marginal necrosis, good growth; 3 heavy leaf spotting and leaf drop with good regrowth; 4 heavy defoliation, stunted growth, very little regrowth. Higher is worse. The steps are descriptions rather than equal intervals, so the difference between 3 and 4 is not the same quantity as the difference between 0 and 1, and the numbers should not be averaged as though they were. Infection was natural and no fungicide was applied against the disease. Standard: Rutgers NJAES bell pepper bacterial leaf spot trial, 2021.

Fruit dimensions measured on a sample from the plot. Wall thickness and fruit dimensions taken on fruit sampled from the plot rather than on the whole harvest, and reported as a plot mean. A figure produced this way describes the fruit that particular planting set in that particular season, and is not a fixed character of the cultivar. Standard: Rutgers NJAES bell pepper trial fruit evaluation.

This trial grew 26 entries. AMSeed publishes results for 5 of them. 21 of the remainder are simply not recorded here yet: the source publishes them and we have not transcribed them, which is unfinished work rather than a judgement about the entries. The point of stating the total is that the trial is represented as what it actually was rather than as the slice we happen to cover.

One site in one season, under natural rather than inoculated infection, so the race pressure is whatever New Jersey supplied that year rather than a controlled challenge. The report notes that all eleven races occur in the state, which means a cultivar resistant to only some of them was exposed to the others here. That makes this a fair test of field performance and a poor test of any particular race resistance, since which race caused a given symptom was not determined.