Prognosis and diagnosis of boron deficiency in blackgram (Vigna mungo L. Hepper) in the field by using plant analysis
Noppakoonwong, R.N., Rerkasem, B., Bell, R.W., Dell, B. and Loneragan, J.F. (1997) Prognosis and diagnosis of boron deficiency in blackgram (Vigna mungo L. Hepper) in the field by using plant analysis. In: Bell, R.W. and Rerkasem, B., (eds.) Boron in soils and plants : proceedings of the International Symposium on Boron in Soils and Plants held at Chiang Mai, Thailand, 7-11 September 1997. Kluwer Academic Publishers, Dordrecht, The Netherlands, pp. 89-93.
From previous glasshouse experiments, 12-18 mg B kg-1 dry wt in the youngest fully expanded leaf blade (YFEL) represents the minimum leaf boron (B) requirement for unrestricted leaf blade elongation (LBE) in black gram (Vigna mungo). A field experiment at Chiang Mai, Thailand was undertaken to test the validity of this B concentration range for diagnosis of B deficiency and to examine the possibility of using B concentration in the YFEL during growth for prognosis of seed yield at maturity. Six levels of B fertilizer (0, 0.5, 1, 2, 4 and 8 kg borax ha-1) and basal fertilizers were applied to 6 replicates. The critical B concentration for diagnosis of pod number in the YFEL at the first mature pod was 13-17 mg B kg- I dry wt being within the range established from the glasshouse experiments. Thus, the functional B requirement for LBE, 12-18 mg B kg-I dry wt in the YFEL, can be recommended for diagnosis of B deficiency in black gram. The critical B ranges in the YFEL for prognosis of seed yield were 31 ± 3, 30 ± 4, 15 ± 1, and 9 ± 1 mg B kg-1 dry wt at the first inflorescence, first pod, first full pod and first mature pod, respectively. The unusually low value of 9 ± 1 mg B kg-1 dry wt is attributed to the recovery of B deficient plants as the result of an increase in B uptake following rain after a drought period. Thus, the use of prognostic values of B deficiency can be limited by the probability of rain after sampling. Despite this limitation, critical values for the prognosis of B deficiency can be used as a guide to the possibility of B deficiency depressing final yield.
|Publication Type:||Book Chapter|
|Murdoch Affiliation:||School of Biological and Environmental Sciences|
|Publisher:||Kluwer Academic Publishers|
|Copyright:||© Kluwer Academic Publishers|
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