Diagnosis of Nutrient Imbalance in Thompson Seedless Grape Grafted on Dog Ridge Rootstock by DRIS

Abstract

A nutrient concentration vs. yield data bank was established for vines grafted on Dog Ridge (Vitis champini) rootstock for developing DRIS ratio norms during bud differentiation stage (BDS) and flowering stages (FS). The data were further subdivided into medium‐ and low‐yielding population based on yield performance. DRIS ratio norms were developed for medium‐yielding population, while diagnoses of nutrient imbalances were made in the low-yielding population. Sixty‐six nutrient expressions were chosen as diagnostic norms. Among the nutrient ratios selected to form diagnostic parameters phosphorus/nitrogen (P/N) (0.260), potassium/nitrogen (K/N) (1.761), phosphorus/zinc (P/Zn) (0.0056) had greater physiological rationale during flowering stage. The ratios of N with P (N/P 3.42) and K (N/K 0.68) were found to be more critical during BDS. Group differences between low‐ and medium‐yielding population were determined using discriminant analysis. The nutrient concentration during FS in medium‐ and low‐yielding populations differed significantly, and magnesium (Mg) accounted for nearly 60.97% of the variation. The difference in mean nutrient concentration during BDS and FS was mainly due to Mg followed in importance by sodium (Na). During BDS Na, followed by Mg and calcium (Ca) were the most common yield‐limiting nutrient, while there was an accompanying excessive accumulation of K, manganese (Mn), and iron (Fe). During FS, Fe, copper (Cu), and K were the most common yield‐limiting nutrients whereas Ca, N, and Mg were on the excessive range.

Keywords:

• DRIS
• grape
• Dog Ridge rootstock
• nutrients