New rice variety tolerates soil salinity, yields high

Scientists have developed and are introducing a climate-smart rice variety that is saline tolerant, important because much of Kenya's soil is salty.

The new rice variety CSR36 is tolerant to saline and sodic (alkaline) soils with pH levels above  8.5.

Dr Ruth Musila, centre director of the Kenya Agricultural and Livestock Research Organisation (Kalro) Mwea, said the CSR36 variety can tolerate pH  9.6 to 9.8, which are quite high.

“When it comes to salt stress, this rice variety can tolerate electrical conductivity of about six to 10,” she said.

She spoke during a farmers’ field day in Hola Irrigation Scheme in Tana River county. It was organised by Kalro in collaboration with the International Rice Research Institute.

Musila said salinity is the excessive accumulation of water soluble salts. Salinity can be caused by poor irrigation practices or insufficient irrigation water to leach the accumulated salts out of the crops' root zone.

“Salinity is often associated with alkaline soils in inland areas where evaporation is greater than precipitation. It is also associated with increased levels of saline groundwater in the irrigated rice fields and intrusion of salt water into low-lying areas near oceans and seas,” she said.

The rice breeder said in under-irrigated field conditions, saline soils can be recognised by the spotty growth of the rice crop and often by the presence of white salt crusts on the surface.

Musila said salinity can be addressed through planting salinity-tolerant rice varieties such as CSR36, submerging the field for two to four weeks before planting rice. This is in addition to observing good agronomic practices and using fertilisers efficiently.

Salinity is a major problem in Kenya especially in the Tana Irrigation Scheme, Mbura Irrigation Scheme and also in Taita Taveta.

She further said when there is a lot of irrigation, the salts rise to the surface. Some of the soils with high salts are not good for rice production because the pH is quite high.

The normal pH for rice production is usually 5.5 to 6.5 but when the soils are saline and sodic the pH goes up to more than 6.5.

“So from this to nine we say that these soils are affected by salts and that is why we are breeding for varieties that tolerate the high pH levels and electrical conductivity.

These varieties are best for these regions affected by salts as they can tolerate the high pH and sodic levels in the soils. The variety can also do well in Bura and Taita Taveta,” she said.

Kalro and the International Rice Research Institute are working on a project to deliver genetic gains to the farmers ito upscale the adoption of climate-smart high-yield rice varieties. 

She said they have carried out trials in 26 locations in the Western, Coastal and Central regions.

The importance of this variety, especially in areas of salt stress is that yields can be as much as five to 5.5 tonnes per hectare.

When a variety is not salt tolerant, you cannot get these yields. The minimum or the maximum is three tonnes per hectare,” the rice breeder said

Musila said the CSR36 variety is early maturing in 120 days. This is equivalent to most varieties being planted.

“It also has other attributes that match the consumers’ preference. For example, the CSR36 has a long slender grain which is non-sticky. It is also aromatic and these are some of the qualities preferred by the consumers,” she said.

“The future for rice production in Kenya is bright because we have the right varieties right now," Musila said.

"What we need to do is to team up with the other rice stakeholders and the private sector. Then we can see the genetic gain in what we have bred goes to the farmers’ fields,” she said.

National Irrigation Authority chief operations officer (COO) Joel Tanui said rice consumption in Kenya is going way beyond the 600,000 metric tonnes per annum.

The national production is slightly less than 300,000 metric tonnes.

To help bridge the gap, Tanui said the authority aims to increase the acreage under irrigation.

“Our major responsibility is to ensure farmers are producing enough maize and rice to feed Kenyans. This year alone, we aim to expand the area under irrigation, specifically for rice, by 20,000 acres,” he said.

According to the NIA, 650,000 acres are currently under irrigation, with 200,000 under rice production.

He said this year the authority is bringing on an additional 20,000 acres.

“In the five-year plan, we want to put another 100,000 acres under rice production so we can bridge the deficit in terms of rice consumption. In all the irrigation schemes, the authority is ensuring  the farmer produces rice at the least cost possible,” Tanui said.

“This is done by making sure operations are at a minimum cost. We want to ensure farmers can offload their rice or maize to the market at an affordable price,” he said.

Tanui said the authority is working towards expansion and rehabilitation of existing irrigation schemes. It is also promoting introduction of high-yielding rice varieties that are climate-smart like the one  Kalro and Irri launched in the Hola Irrigation Scheme.

He said this is a milestone in ensuring increased productivity and income of the farmer while addressing food and nutrition security. 

“We are looking at it from three aspects," Tanui said.

"As an authority, we are promoting new varieties at the same time we are improving irrigation facilities so we are efficient in our operations and reduce the cost.

"This will ultimately help the farmer meet the market demand of supplying rice at an affordable price,” he said.

(Edited by V. Graham)