Effect of black point on seed quality and germination of wheat

Introduction

Wheat is the mandatory staple food crop for around 36 per cent of the global population (Kumar et al., 2019) [12] . Wheat belongs to the Family Poaceae (Braun et al., 2010) [4] . Wheat contributes more calories and proteins to the world diet than any other cereal crops (Adams et al., 2002 and Shewry, 2009) [1,27] . It is nutritious, easy to store and transport and can be processed into various types of food. Wheat flour is used to prepare bread, produce biscuits, confectionary products, noodles and vital wheat gluten or seitan. Wheat is considered good source of protein, dietary fiber, B-group vitamins and minerals. It is an excellent food for health building. Several biotic stresses restrict wheat production. More than 200 diseases affect wheat, around 50 of them lead to significant economic damage (Al-Sadi, 2016; Lalic et al., 2017; Riaz et al., 2017 and Sharma et al., 2017) [3,13,24,26] . Approximately 20 per cent of the wheat crop is lost annually due to diseases. Major diseases of wheat include rusts, spot blotch, common root rot, smut, tan spot, septoria blotch, powdery mildew, fusarium head blight and blast. Black point is mainly cause by Alternaria alternata then followed by Bipolaris sorokiniana, Curvularia lunata, Cladosporium cladosporioides, Cochliobolus sativus and Fusarium spp. (Fakir et al., 1989; Dey et al., 1992; Fernandez and Conner, 2011) [7,5,8] . The black point disease was identified by a dark discoloration of the embryo sides of the wheat grains (Mak et al., 2006) [15] . Black point formation in susceptible varieties is linked to conditions of low vapour pressure deficit, low temperatures and high humidity. The development of symptoms depends on both environmental conditions and biotic factors during the grain development and ripening stages. Black point negatively affects germination and seedling emergence (Rahman and Islam, 1998) [21] . The decline in germination is associated with the level of black point severity (Malaker and Mian, 2002) [16] . Infection increase when extended wet conditions occur during the grain-filling stage. The disease is identified by brown to black discoloration that is typically confined to the embryo end of the kernel, while under severe infection the entire grain can become discolored and shriveled (Adlakha and Joshi, 1974) [2] .

Materials and Methods

The present experiment was conducted at Research farm, Wheat Research Station, Junagadh Agricultural University, Junagadh during 2025-2026 in Rabi season. Ten wheat varieties (GW 366, GW 451, GW 322, GW 496, DBW 110, GW 273, GW 173, LOK 1, GJW 463 and GW 513) were taken for study of black point impact on seed quality and germination. Healthy and black point infected grains were utilized for study the impact on quality parameters like grain weight with the use of digital balance in laboratory. For the determination of germination per cent 100 seeds per wheat varieties were taken. Infected seeds of each variety were surface sterilized with 2 per cent sodium hypochlorite solution for 1 minute, followed by rinsing with sterilized distilled water with three times. After sterilization, seeds were transferred to 9 cm Petri dishes (50 seeds per Petri dish) with two layers of blotter paper fully moistened with sterilized distilled water for germination. The Petri dishes were incubated in a growth chamber at 28 ± 1°C in darkness for three days at 90-95 per cent relative humidity and a 12 hrs. photoperiod with the same temperature (Li et al., 2014) [14] . Germination percentages were calculated after 7 days by counting the germinated seeds using the formula mentioned below (Momtaz et al., 2022) [17] .

To measure the 1000 grain weight.

Germination Percentage =

Total number of germinated seed Total number of seeds tested ×100

The seeds were sorted out into 6 different grades on the basis of severity of black point infection (Table 1) [Plate 1 (A)]. The grading was done according to a 0-5 rating scale as suggested by Gilchrist (1985) [9] . Based on grade of infection the infected seed germination percentage was also assessed at Laboratory condition. Method follow for germination determination was same as earlier given.

Result and discussion

The data presented in The results obtained in present study were similar with results of Partap and Solanki (2016) [19] . They founded that seeds weight increase with more disease incidence, in their experiment founded that seed weight of healthy and infected seed was 41.65 and 48.08 g, respectively. This experiment finding was also similar with result of Khulbe et al. (2011). They also founded that seed weight increase with increase the disease grade. The results obtained in present study on germination of seed were corroborate with more or less similar type of results as obtained by Momtaz et al. (2022). They reported about 95 to 89 per cent of germination was recorded for the seven wheat varieties in healthy seeds after 7 days, but in infected seed it was reduced from 84 to 76 per cent. Sharma et al. (2021) [25] also revealed that infection of black point in seeds reduced the germination. Similarly, Yadav et al. (2020) [29] observed that black point significantly decreased the germination percentage in infected seeds. Li et al. (2014) [14] also studied about germination percentage more decrease in grade 3 to 5, whereas in grade 1 and grade 2 no significant difference has been observed. G0: Grains free from any discoloration (apparently healthy) G1: Only tip of the embryo brown to blackish G2: Discoloration covering the whole embryo G3: Embryo with 1/4 of the grain discolored G4: Embryo with 1/2 of the grain discolored G5: Embryo with more than 1/2 of the grain discolored and shriveled

Conclusions

Black point complex disease negatively impacted seed quality traits across wheat varieties. Seed weight of infected seed was increasing compare to healthy seeds. Germination per cent decrease in infected seeds compare to healthy seeds due to shrivelling and undersized seeds in black point infection.

References

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