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Healthy seedlings are the most important prerequisite for any vegetable crop to reach its full output potential. As a result, large-scale seedling production is becoming a profession and a commercial activity. Farmers used to generate seedlings at a reasonable cost in nursery beds in the past. However, due to some drawbacks like poor germination, higher pest and disease incidence, poor field establishment etc. in traditional nurseries, many progressive farmers and agriculture entrepreneurs have turned their attention to the commercial production of quality seedlings utilising seedling trays or pro-trays. In this background, the present study entitled ‘Standardisation of operational procedures for pro-tray seedling production of vegetables’ was undertaken with the objective of standardising best growing media, pre-sowing seed invigoration, and evaluating the effect of biofertilizer on pro-tray seedling production of vegetables. The present study was carried out at the Department of Vegetable Science, College of Agriculture, Vellanikkara as three experiments during 2020-21. All three experiments were conducted in a Completely Randomized Design with three replications. In the first experiment seeds of tomato var. Anagha, chilli var. Anugraha, cucumber var. Heera, and okra var. Salkeerthi collected from the Department of Vegetable Science were sown in seventeen different media that were initially analysed for various physicochemical properties. The growth parameters of the seedlings raised in the poly house were assessed at the stage of commercial sale of each crop i.e., 15 days after sowing (DAS) in cucumber and okra and 30 DAS in chilli and tomato. The results showed that T13 (cocopeat: vermiculite: perlite - 1:1:1) and T17 recorded comparatively minimum bulk density, maximum water holding capacity and porosity which are desirable physical properties for good seedling growth. T17 (coir pith compost: vermiculite: perlite - 3:1:1) was found to be the best soil-less media for all four crops based on growth parameters and cost analysis. Among soil containing media T6 having soil and dried powdered cow dung in equal proportion and T10 having soil, cocopeat and dried cow dung exhibited a higher benefit cost ratio and was found to be on par with T17 for most of the growth parameters. Farmers do not have easy access to vermiculite and perlite, and they are costly. In this context,
soil, cocopeat and dried powdered cow dung in equal proportion is found to be an
alternate media comprising locally available inputs and affordable by the farmers.
The best media from the first experiment was chosen for further trials. The
second trial comprised of nine different seed treatments including various
concentrations of KNO3 and Pseudomonas. Pre-sowing seed invigoration with 0.5%
KNO3 in combination with 1% Pseudomonas was found to be highly effective in
improving germination and growth parameters viz., germination percentage, plant
height, root length, vigour index Ⅰ & Ⅱ and chlorophyll content of seedlings of
tomato, chilli, cucumber and okra. This combination has the dual advantage of
providing potassium and nitrogen to the seedlings and imparting resistance from
diseases especially damping off. So, these treatments can be effectively utilized for
producing healthy and vigorous vegetable seedlings.
The third experiment included nine treatments in which different biofertilizers
viz., PGPR Mix-1, Pseudomonas fluorescense, Trichoderma asperellum and
arbuscular mycorrhizal fungi were inoculated in the media individually and in
combination. Evaluation of the effect of biofertilizers showed that higher growth
parameters like plant height, root length, leaf area, collar girth, vigour index Ⅰ and
vigour index Ⅱ are comparatively higher in the treatment containing PGPR, AMF and
along with either Pseudomonas or Trichoderma.
In the above three experiments the best treatments were identified by ranking
based on an index derived from principal component analysis. The characters viz.,
number of leaves, leaf area, collar girth, vigour index Ⅰ & Ⅱ and total chlorophyll
content was used for performing PCA. The loadings of principal component having
Eigen value more than one was taken as weightage. Using weightage, an index was
derived and the treatments having higher index was ranked higher. The best media
obtained include cocopeat: vermiculite: perlite (3:1:1) and soil: cocopeat: cow dung
(1:1:1). A combination of 0.5% KNO3 and 1% Pseudomonas was the best seed
invigoration treatment. Among different biofertilizers evaluated the combination of
AMF, PGPR Mix-1 and Pseudomonas was found to be the best. Based on the insights
of the above three trials, standard operational protocol for seedling production of tomato, chilli, cucumber and okra is generated for use by farmers.

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