Relationships of spectral traits with yield and nutritional quality of snap beans (Phaseolus vulgaris L.) in dry seasons

ABSTRACT

Four snap bean varieties (green and yellow-podded) were grown in three water supplies (regularly irrigated, deficit-irrigated and non-irrigated) in order to examine the spectral reflectance at leaf and canopy levels, leaf area index (LAI) and their relationships with the yield and nutritional quality at the University of Debrecen, Debrecen, Hungary from 2011 to 2013. Under non-irrigated condition, the plant height decreased, SPAD values were high but LAI and normalized difference vegetation index (NDVI) were low. The difference in SPAD values was higher between the varieties during flowering under non-irrigated condition and it was more pronounced during pod development using deficit irrigation. In dry years, non-irrigated condition SPAD did not correlate with the yield but during pod development it was correlated with the dry matter content of the pods. The relationship of SPAD with protein and crude fiber content of pods was strongly dependent on the cropping years. Under deficit-irrigated condition, NDVI measured during flowering and pod development correlated closely with the yield where a higher NDVI (0.85) predicted either 6 or 9.5 t ha⁻¹ of yield depending on the variety. Under this condition Serengeti variety with green pods was prominent based on the studied traits among the varieties.

KEYWORDS:

• Snap bean
• drought
• SPAD
• NDVI
• nutritional quality

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by a grant from the National Technology Program of Hungary (NKTH No. 00210/2008) and the FP7-REGPOT-2010-1 UD_AGR_REPO University of Debrecen REGPOT Capacities Project. The publication was supported by the EFOP-3.6.3-VEKOP-16-2017-00008 project. The project is co-financed by the European Union and the European Social Fund.