*DOI: http://dx.doi.org/10.5772/intechopen.112322 Accelerating Breeding for Drought Tolerance in Sorghum (*Sorghum bicolor*): An Integrated…*

cultivars from the breeding program following six year breeding program to release. That is; from germplasm evaluation through initial screening, making crosses, advancing populations (F1–F5) as single plants selections under the pedigree system. This is followed by stages of preliminary yield trials (PYT) and advanced yield trials (AYT) in designated places. It is then followed by adaptation trials, national performance tests and release. Yield improvements currently have stagnated and there is a need to replace the current varieties released five years ago but suitable to dry lowland agroecology. Therefore participatory evaluation of potential candidate cultivars for replacement was done in 2017 B (short rain season), to set better targets for innovative breeding and selection approaches. This was to enhance the germplasm base for key traits that stabilize production and could increase genetic gains in farmers' fields (**Table 1**). This summarizes the priority traits related to drought tolerance and drought escape given by the two groups of sorghum farmers, during the field day organized for the Teso and the Lango farmers of Uganda in the 2017 B season. These groups of farmers are from different sorghum production systems. The participants were encouraged to screen the on-station field experiment block and pick up the eye-catching ones for in-depth discussion. The scores and ranks for each group were summarized into four categories. The prioritization of drought tolerance and escape were mentioned along with the description of traits that will contribute to the stability of production (**Table 1**). Specific ranking based on value for use (**Table 2**) and ranking based on gender following focus group discussions in the field (**Table 3**).


#### **Table 1.**

*Prioritization of identified selection traits by two participatory groups. Each group consisted of a random mix of six researchers and 30 farmers male and female. The farmers ranked groups of perceived drought tolerance traits from 1 to 4 and rated from 1 to 4 in order of priority.*


**Table 2.**

*Matrix ranking of traits by farmers (based on value for use), by pairwise wise ranking method.*

*Case Studies of Breeding Strategies in Major Plant Species*


*DOI: http://dx.doi.org/10.5772/intechopen.112322 Accelerating Breeding for Drought Tolerance in Sorghum (*Sorghum bicolor*): An Integrated…*

#### **Table 3.**

*Ranking based on gender following focus group discussions in the field.*

#### **1.3 Results and discussion**

High-valued traits considered for drought tolerance and escape by farmers are high plant vigor and robustness to nurture the seeds of high quality and hence high yield. These traits were identified from three genotypes; KAK-7780, IESV 24029SH and SESO3. Further description of the robustness trait takes care of plant health and associated responses to biotic and abiotic stresses (pests, diseases, drought and soil fertility). Additionally, it dictates the maturity and uniformity of the crop and hence was rated highly by participating farmers. Drought is a complicated trait to screen; robustness and vigor show good nutrition and good germination. This is how farmers quickly demonstrate yield potential. Furthermore, farmers emphasized morphological traits that breeders do not systematically select for. Breeders, on the other hand, rely on quantitative measurements but are aware of the heritability of specific traits and the influence of genotypes by the environment on plants growing under optimal conditions. Therefore, observed selection goals of farmers and breeders fit into the description of [8]**,** who stated that science takes a reductionist approach toward breeding that is, to reduce the number of variables considered but study them in detail. Farmer's positive selection in favor of healthy, good germinating, vigoros, large panicles and large seeds demonstrate their ability to select stable genetic responses. These selection traits have actual advantages on yield under rain-fed conditions. Number of factors have been found to be associated with resistance in sorghum and include; seedling vigor, glossiness, morphological and biochemical characteristics. Any condition such as drought, low fertility and temperature makes the plant susceptible to attack by insect pests and diseases [9]**.** Besides involving farmers in target setting and selection, it is important to consider the selection environment. Selection is more efficient when the correlation between selection and the target environment is high and increases selection efficiency for direct and indirect selection for broader or specific adaptation [10]**.** This study recommends selection indices that will help in selecting seedlings at a very early stage without losing important information. The farmers and scientists preferred selections made from advanced lines to be planted in regional adaptation trials to

analyze genotype by environment interaction to prove the need for more varieties to be released with certainty. This will help define clusters of target environments based on differences in environmental parameters, production systems, and farmer preferences [11]. From the participatory study; drought resistance is best measured in terms of robustness (vigor) and plant health traits as priority traits when designing product profiles (**Table 2**).

#### **1.4 Sectional conclusion**

Several relevant traits are often considered simultaneously in plant breeding, particularly when selection is done by farmers. The relationship among them determines breeding strategies and response to selection (study 2). There is a need to develop an index which when applied to sorghum seedlings during the first eight weeks of development in the field (at anthesis), will indicate the best progenies and best plants within the progeny. The possible vigor parameters associated with drought tolerance include; Plant height, node diameter, basal stem sugar, internode length, Leaf area, leaf dry weight and stay green from where correlations can be calculated from non-senescent genotypes. Some of these traits identified can reasonably be bred depending on their level of expression. Therefore, it is a need to conduct multi-location trials to help to monitor levels and expression of adaptive associated traits in plants that will be incorporated into the model while taking account of environmental variance in the expression of traits.
