Investigation of the proline role in controlling traits related to sugar and root yield of sugar beet under water deficit conditions

Abstract

Sugar beet (Beta vulgaris L.), accounting for 30 percent of the total world sugar production, maybe affected by drought in terms of both its yield and quality. Proline is an amino acid with pivotal role in plant responses to drought stress. The present experiment was conducted at two locations during 2015. The treatments included 100 %, 75 %, and 50 % irrigation water requirements (IWR) and 0, 5, and 10 mM of proline. Drought stress reduced root diameter and length, K content, alkalinity coefficient, molasses content, root yield, and white sugar and sugar yields, but increased leaf and root proline content, Na, α-N, and sugar and white sugar contents. However, proline application improved yield and food quality of sugar beet and 10 mM proline was more effective. Sugar and white sugar yields increased by 18 % and 15 % by 10 mM proline respectively. Combination of 50 % IWR and 10 mM proline application increased root yield by 26 % as compared to drought stress alone. The results showed that proline is the most sensitive osmoticum in sugar beet’s response to water stress and improvement in water relations and osmoregulatory measure in yield and quality of sugar beet.