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Parameters arrived through growth analysis
1) Leaf Area (LA) X
LA = ---------- x B
A Where X = known area of leaves The leaf area of standard leaves, usually 3rd leaf from the top is measured and dried.A = dry weight of known area of leaf B = dry weight of unknown area of all leaves B) Linear measurement method LA = LBK (cm2 or m2) Where L=maximum length, B=maximum breadth, K=constant (can be worked out by regression analysis)
K value may not be the same for different varieties in the same species. 2) Leaf Area Index (LAI)
Total leaf area of the plant
Leaf area index = -----------------------------------------------------
Ground area occupied by the plant (spacing) 3) Leaf Area Ratio (LAR) Leaf area per plant LAR = ----------------------------- Total plant dry weight 4) Leaf Area Duration (LAD) L1 + L2 LAD = ----------------- x (t2 – t1) 2 Where LAI (i) – Leaf area index at first stage LAI (ii) - Leaf area index at second stage t2 –t1 – Time interval between the two consequent stages and expressed in days. 5) Leaf Area Ratio (LAR) L1 + L2 LAD = ----------------- x (t2 – t1) 2
Leaf area SLA = -------------------------- Leaf dry weight 7) Specific Leaf Weight (SLW) Leaf weight SLW = ----------------- Leaf area 8) Leaf Weight Ratio (LWR) Leaf dry weight LWR = ---------------------------------------- Total plant dry weight 9) Net Assimilation Rate (NAR) Where Log e L2 = Natural log of leaf area at stage 2. Log e L1 = Natural log of leaf area at stage 1. L2 & L1 = Leaf area at stage 2 & 1 respectively W2 & W1 = Dry weight of the whole plant at stage 2 & 1 respectively t2-t1 = Time interval between the two stages NAR is expressed as mg cm-2 day -1 10) Relative Growth Rate (RGR) Loge W2 – loge W1 RGR = ----------------------- t2 – t1 W2 & W1 = Whole plant dry weight at t2 & t1 respectively and expressed as g g-1 day-1 11) Crop Growth Rate (CGR)Where, W2 and W1 are total plant dry weight at time t2 and t1 and P is plant population per unit area. CGR is also the product of leaf area index and net assimilation rate. CGR = LAI X NAR CGR increases as LAI increases to an optimum because of greater light interception. CGR is expressed as mg m-2 day -1. 12) Harvest Index (HI) |
Last modified: Wednesday, 13 June 2012, 6:34 AM