Effects of sampling time and plant tissue on vascular colonization intensity by Fusarium oxysporum f. sp. ciceris (Foc) races 0 and 5 in chickpea cultivars showing differential resistance.

aPlants were grown hydroponically in a growth chamber at 25±2°C and a 14-h photoperiod of fluorescent white light of 360 µE m−2 s−1 in an orbital shaker at 120 rpm. Plants were sampled at 2 days intervals from 6 to 18 days after inoculation (dai). Tissues sampled included: Root: lower and intermediate zone of the tap root; Hypocotyl and epicotyl: zones immediately before and after the insertion of cotyledons, respectively; Stem: internodes one to third of the main stem. Four plants (two plastic vessels) per F. oxysporum f. sp. ciceris race/chickpea cultivar combination were analysed at each sampling time. The experiments were arranged in a randomized complete blocks design, and were repeated twice. For each sampled tissue, vascular colonization was assessed on four blocks with 20 cells (xylem vessels) per block, covering the entire vascular cylinder.bLinear single-degree of freedom contrasts were computed to test the effect of selected experimental treatment combinations at PcExperimental combinations in which no disease symptoms developed.dUnderlined values indicate that estimated value for the first term of the contrast was lower than that of the second term.