GREENHOUSE IRRIGATION SYSTEMS AFFECT GROWTH OF TAM-MILD JALAPENO-1 PEPPER SEEDLINGS

Two studies were conducted to determine how greenhouse irrigation syst ems alter root elongation, root morphology, shoot growth, and water st atus of 'TAM-Mild Jalapeno-1' pepper (Capsicum annuum L.) seedlings. T ransplants were grown in containerized trays for 48 days in a greenhou se. Irrigation systems were 1) flotation (FI), 2) 28 days FI plus 14 d ays overhead (OI; FI + OI), 3) alternate OI and FI (OI-FI), and 4) OI. FI and OI-FI transplants maintained a uniform lateral root length inc rease between 20 and 41 days after seeding (DAS). In FI + OI and OI tr ansplants, lateral root elongation tended to plateau at almost-equal-t o 31 DAS; however, by increasing the number and length (33%) of basal roots, OI transplants had a total root growth compensation during the remaining growth period. At 41 DAS, OI transplants had a higher shoot: root ratio (S:R = 5) and maintained a higher shoot water potential (P SI(stem) = -0.58) than FI transplants (S: R = 3; PSI(stem) = -0.69 MPa , respectively). In the second study, OI transplants maintained higher PSI(stem) than FI transplants. The latter had a lower stomatal conduc tance and photosynthesis rate than OI and FI + OI transplants. FI may be used to lower the S : R ratio and promote hardiness in jalapeno tra nsplants.