The Effects of Different Seed Priming Chemicals on Germination and Seedling Growth Rate of Maize (Zea mays L.) in Lesotho

Lesotho is among the nations with inhabitants consuming maize as a staple food prepared in various dishes. Almost all farming households grow maize for both home consumption and animal feeding. Morojele and Sekoli (2016) [1] state that maize is a major staple crop in Lesotho as evidenced by number of farmers (195,958) involved in its production, proportion of area under which it is grown (146,313 ha) and the rate at which it is consumed (266,755 metric tons) [2]. Maize ranks first among cereal crops grown in Lesotho, followed by sorghum, wheat and beans [3]. It is cultivated across all agro-ecological zones of Lesotho, namely; low-lands, foot-hills, mountains and Orange River valley. Among the four ecological zones of Lesotho, lowlands account for the highest maize production reaching 15, 800 tons on 118 586 hectares. The lowest production is in the Orange River Valley where 1,475 tons is achieved on 2,757 hectares (2021). Foothills and mountain zones are at par. In the lowlands, arable area put under maize is larger than in the other zones because of both suitable climatic and edaphic conditions prevailing and along growing season, from October to December. In the foothills and mountain zones, planting can only commence in September and terminate in November due to early chilling and freezing injuries that the crop suffers [3]. The Orange River Valley is prone to drought and is very hot and dry in summer resulting in maize crops being adversely affected in terms of growth, development and grain yield [1], [4].

The Basotho nation perceives maize as one of the crops contributing significantly to the household economy, particularly when all farmers consume it and sell the surplus to community members in the neighborhood generating income for purchasing other household needs [5], [6]. The importance of maize to the Basotho nation cannot be over-emphasized as amain source of nutrients particularly energy and other elements. Nutritionally, carbohydrates (70-87 %), proteins (6-13 %), fiber (7%), oil (2-6 %), vitamin Band minerals constitute maize grain [7], [8]. For maize to be a balanced diet, it is complemented by the common bean, which has essential amino acids devoid in maize such as lysine. Lysine plays a critical role in post-translational modifications facilitated by enzymes Lysol hydroxylase and Lysol oxidase, which are directly involved in the synthesis and maturation of collagens [9]. Farmers cook and prepare maize with various forms of relish such as immature pods of beans and peas, pumpkin, indigenous and exotic vegetables. Besides maize being consumed by Basotho, it is also used to feed domestic animals as grains or plant residues during the winter, when feed resources are very scarce [1]. The economic importance of maize in Lesotho cannot be over-emphasized as afore-mentioned necessitating a boast in productivity, which will translate into increased national production. It is therefore imperative to identify factors that determine the optimum growth rate, good standability in the field, high grain yield and quality of maize crops in Lesotho.

These factors when applied accordingly will enable Lesotho to meet its requirement for maize and export surplus elsewhere. According to Anazco et al., (2023) [9], the primary causes of low productivity and poor standability are low seed germination rate and emergence of weak seedling above the soil surface. Reed et al., (2022) highlighted that seed germination and quality tests are performed in the laboratory before the seed is released to the farmers for sale with a germination percentage of 85%, which must be declared officially on the label. In Lesotho, such seeds with declared germination percentages result in low germination rates and weak seedling emergence above the soil surface in the field. The low germination emergence rate is attributed to the time elapsed from planting to emergence above the soil surface. Longer elapsed period results in low germination, which in turn culminate into poor crop stand. It is only through seed priming that germination rate and period can be enhanced, which triggers germination mechanism and processes [10], [11]. Seed priming is crucial as the main source of water for germinating seed and producing stronger seedlings where soil moisture is inadequate to initiate a germination process [12]. Insufficient soil moisture can contribute to delay or uneven germination, resulting in poor seedling establishment and crop yield [13]. Several studies validate the notion that when maize seeds are soaked in water before sowing, germination is enhanced, thus such practice increases the chances of growing faster than when such a method is not applied at all [14], [15]. Besides, many researchers discovered that certain chemical compounds are more potent in enhancing germination than pure distilled water when proper procedure is followed and modified accordingly [16], [17]. The seed priming methods such as hydro-priming, halo-priming, osmo-priming and solid matrix priming were introduced and adopted to enhance seed germination elsewhere [18], [19]. Hence, the study explored the effects of different seed priming chemicals on the germination and seedling growth rate of maize (Zea Mays L.). Specific objective of the study was to (i) identify the most potent chemical compounds that enhance high germination and seedling growth rate of maize.