पौधों में एब्सिसिक एसिड (ABA) के बारे में निम्नलिखित कथनों में...

सभी विषय सामान्य कृषि, फसल उत्पादन एवं मृदा विज्ञान कोशिका विज्ञान, आनुवंशिकी, कार्यिकी, जैव रसायन एवं पादप सुरक्षा आनुवंशिकी, पादप रोग विज्ञान, बीज विज्ञान एवं कृषि सूक्ष्मजीव विज्ञान खाद्य व औद्योगिक सूक्ष्मजीव विज्ञान, ग्रामीण विकास एवं कृषि अनुसंधान संरचना

Q.21

ICAR AIEEA PG 2024 - Plant Sciences

MCQ (Single Correct) +4 −1

Which of the following combinations of the premises of 'Gamete Selection' in plant breeding is the correct one?
(A) Multiparent crosses are required for simultaneous improvements of multiple traits.
(B) The male parents of the final crosses are heterozygous and hence heterogametic.
(C) Each zygotic seed is a product of a separate, independent fertilization event.
(D) Gametic selection is an effective method to isolate an inbred for hybrid breeding.
Choose the correct answer from the options given below:

पादप प्रजनन में 'युग्मक चयन' (Gamete Selection) के आधार-वाक्यों (premises) का

निम्नलिखित में से कौन सा संयोजन सही है?
(A) कई लक्षणों में एक साथ सुधार के लिए बहु-जनक संकरण (multiparent crosses) आवश्यक हैं।
(B) अंतिम संकरण के नर जनक विषमयुग्मजी होते हैं और इसलिए विषमयुग्मकी (heterogametic) होते हैं।
(C) प्रत्येक युग्मनज बीज एक अलग, स्वतंत्र निषेचन घटना का परिणाम होता है।
(D) युग्मक चयन संकर प्रजनन के लिए अंतःप्रजात (inbred) को अलग करने की एक प्रभावी विधि है।
नीचे दिए गए विकल्पों में से सही उत्तर चुनिए:

(A), (B) and (C) only केवल (A), (B) और (C) (A), (B) and (D) only केवल (A), (B) और (D) (A), (C) and (D) only केवल (A), (C) और (D) (B), (C) and (D) only केवल (B), (C) और (D)

Gamete Selection in Plant Breeding:

Developed by L.J. Stadler (1944) for developing inbred lines from open-pollinated varieties in cross-pollinated crops like maize.
Key premises of gamete selection:

Multiparental or heterogeneous background (A): Outcrossing populations or multiparent crosses provide wide genetic variability across multiple agronomic traits.
Heterozygous / heterogametic male parents (B): When an $F_1$ or heterozygous population serves as pollen donor, each pollen grain represents a unique recombinant gamete.
Independent fertilization events (C): Each individual kernel/seed on the ear is formed by an independent fertilization event between an egg cell and a unique male gamete.
- Gamete selection evaluates the performance of gametes from open-pollinated varieties by crossing them directly to an elite inbred tester early in the program.

Therefore, premises (A), (B), and (C) are the foundational premises of gamete selection. Correct Answer: Option 1 ((A), (B) and (C) only).

विस्तृत व्याख्या:

Gamete Selection in Plant Breeding (युग्मक चयन के सिद्धांत - Stadler, 1944):

Developed by L.J. Stadler (1944) for developing inbred lines from open-pollinated varieties in cross-pollinated crops like maize.
Key premises of gamete selection:

Multiparental or heterogeneous background (A): Outcrossing populations or multiparent crosses provide wide genetic variability across multiple agronomic traits.
Heterozygous / heterogametic male parents (B): When an $F_1$ or heterozygous population serves as pollen donor, each pollen grain represents a unique recombinant gamete.
Independent fertilization events (C): Each individual kernel/seed on the ear is formed by an independent fertilization event between an egg cell and a unique male gamete.
- Gamete selection evaluates the performance of gametes from open-pollinated varieties by crossing them directly to an elite inbred tester early in the program.

Therefore, premises (A), (B), and (C) are the foundational premises of gamete selection. Correct Answer: Option 1 ((A), (B) and (C) only).

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

Q.22

ICAR AIEEA PG 2024 - Plant Sciences

MCQ (Single Correct) +4 −1

Which of the following statements about synthetic varieties are correct?
(A) Unlike hybrids, the farmers can save the seeds of synthetic varieties.
(B) Synthetic varieties have wider adaptability.
(C) No need to make fresh crosses every year.
(D) Synthetic varieties are higher yielding than the hybrids.
Choose the correct answer from the options given below:

संश्लिष्ट किस्मों (synthetic varieties) के बारे में

निम्नलिखित में से कौन से कथन सही हैं?
(A) संकरों (hybrids) के विपरीत, किसान संश्लिष्ट किस्मों के बीज बचाकर रख सकते हैं।
(B) संश्लिष्ट किस्मों में व्यापक अनुकूलन क्षमता (wider adaptability) होती है।
(C) प्रत्येक वर्ष नए संकरण बनाने की आवश्यकता नहीं होती है।
(D) संश्लिष्ट किस्में संकरों की तुलना में अधिक उपज देने वाली होती हैं।
नीचे दिए गए विकल्पों में से सही उत्तर चुनिए:

Synthetic Varieties in Cross-Pollinated Crops:

synthetic variety is developed by intermating a group of inbred lines or clones that have been evaluated for general combining ability (GCA), followed by open pollination.
Advantages of Synthetics:
Seed saving (A): Farmers do not need to buy fresh certified seeds each season; they can save and re-sow their harvested seed for 3–4 generations without substantial loss of vigor.
Broad genetic base & wide adaptability (B): Due to heterogeneity and heterozygosity, synthetics exhibit dynamic buffering and wide climatic stability across diverse environments.
Cost-effective seed production (C): There is no need for laborious annual hand emasculation/crossing or CMS seed production plots required for $F_1$ hybrids.
Statement (D) is false: Single-cross $F_1$ hybrids exploit both GCA and specific combining ability (SCA) and almost invariably yield significantly higher than synthetic varieties.

Hence, statements (A), (B), and (C) are correct. Correct Answer: Option 1 ((A), (B) and (C) only).

विस्तृत व्याख्या:

Synthetic Varieties in Cross-Pollinated Crops (संश्लिष्ट किस्में):

synthetic variety is developed by intermating a group of inbred lines or clones that have been evaluated for general combining ability (GCA), followed by open pollination.
Advantages of Synthetics:
Seed saving (A): Farmers do not need to buy fresh certified seeds each season; they can save and re-sow their harvested seed for 3–4 generations without substantial loss of vigor.
Broad genetic base & wide adaptability (B): Due to heterogeneity and heterozygosity, synthetics exhibit dynamic buffering and wide climatic stability across diverse environments.
Cost-effective seed production (C): There is no need for laborious annual hand emasculation/crossing or CMS seed production plots required for $F_1$ hybrids.
Statement (D) is false: Single-cross $F_1$ hybrids exploit both GCA and specific combining ability (SCA) and almost invariably yield significantly higher than synthetic varieties.

Hence, statements (A), (B), and (C) are correct. Correct Answer: Option 1 ((A), (B) and (C) only).

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

Q.23

ICAR AIEEA PG 2024 - Plant Sciences

MCQ (Single Correct) +4 −1

Which combinations of the following statements about Abscisic Acid (ABA) in plants are correct?

(A) ABA is important for plant development and desiccation tolerance.

(B) ABA influences the expression of various genes, including the gene for Late Embryogenesis Abundant (LEA) proteins.

(C) ABA also regulates the closure of aquaporins.

(D) Like GAs, the ABA also strongly promotes early flowering in plants.

Choose the correct answer from the options given below:

पौधों में एब्सिसिक एसिड (ABA) के बारे में निम्नलिखित

कथनों में से कौन सा संयोजन सही है?
(A) ABA पादप विकास और शुष्कन सहनशीलता (desiccation tolerance) के लिए महत्वपूर्ण है।
(B) ABA विभिन्न जीनों की अभिव्यक्ति को प्रभावित करता है, जिसमें लेट एम्ब्रियोजेनेसिस एबंडेंट (LEA) प्रोटीन का जीन भी शामिल है।
(C) ABA एक्वापोरिन (aquaporins) के बंद होने को भी नियंत्रित करता है।
(D) जिबरेलिन (GAs) की तरह, ABA भी पौधों में शीघ्र पुष्पन को दृढ़ता से बढ़ावा देता है।
नीचे दिए गए विकल्पों में से सही उत्तर चुनिए:

Functions of Abscisic Acid:

Statement (A) is CORRECT: Known as the primary stress hormone, ABA promotes seed maturation, accumulation of nutrient reserves, and desiccation tolerance during late embryogenesis.
Statement (B) is CORRECT: ABA induces transcription of genes encoding osmoprotectants and LEA (Late Embryogenesis Abundant) proteins that protect cellular membranes and enzymes against dehydration damage.
Statement (C) is CORRECT: ABA modulates water flow and cellular hydraulic conductivity by regulating the gating/closure of plasma membrane aquaporins (water channels) and triggering stomatal closure in guard cells.
Statement (D) is INCORRECT: Gibberellins (GA) promote bolting and flowering, whereas ABA typically represses vegetative growth, enforces dormancy, and delays flowering in most plant species.

Thus, statements (A), (B), and (C) are correct. Correct Answer: Option 1 ((A), (B) and (C) only).

विस्तृत व्याख्या:

Functions of Abscisic Acid (एब्सिसिक अम्ल के कार्य - स्ट्रेस हॉर्मोन):

Statement (A) is CORRECT: Known as the primary stress hormone, ABA promotes seed maturation, accumulation of nutrient reserves, and desiccation tolerance during late embryogenesis.
Statement (B) is CORRECT: ABA induces transcription of genes encoding osmoprotectants and LEA (Late Embryogenesis Abundant) proteins that protect cellular membranes and enzymes against dehydration damage.
Statement (C) is CORRECT: ABA modulates water flow and cellular hydraulic conductivity by regulating the gating/closure of plasma membrane aquaporins (water channels) and triggering stomatal closure in guard cells.
Statement (D) is INCORRECT: Gibberellins (GA) promote bolting and flowering, whereas ABA typically represses vegetative growth, enforces dormancy, and delays flowering in most plant species.

Thus, statements (A), (B), and (C) are correct. Correct Answer: Option 1 ((A), (B) and (C) only).

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

Q.24

ICAR AIEEA PG 2024 - Plant Sciences

MCQ (Single Correct) +4 −1

The characteristic features of monocot seeds include-

(A) Seeds germinate bearing a short axis called Plumule and Radicle.

(B) Plumule and Radicle are enclosed in a sheath called Coleoptile and Coleorhiza, respectively.

(C) The radicle grows downward and develops into the root system.

(D) The cotyledon of the seeds of the monocot crop Sorghum (Jowar) is known as 'Husk'.

Choose the correct answer from the options given below:

एकबीजपत्री (monocot) बीजों के विशिष्ट लक्षणों में शामिल हैं:

(A) बीज अंकुरित होकर एक छोटा अक्ष धारण करते हैं जिसे प्रांकुर (Plumule) और मूलांकुर (Radicle) कहा जाता है।

(B) प्रांकुर और मूलांकुर क्रमशः प्रांकुरचोल (Coleoptile) और मूलांकुरचोल (Coleorhiza) नामक आवरण में बंद होते हैं।

(C) मूलांकुर नीचे की ओर बढ़ता है और मूल तंत्र (root system) के रूप में विकसित होता है।

(D) एकबीजपत्री फसल ज्वार (Sorghum) के बीजों के बीजपत्र को 'भूसी' (Husk) के रूप में जाना जाता है।

नीचे दिए गए विकल्पों में से सही उत्तर चुनिए:

Morphology of Monocot Seeds:

Statement (A) is CORRECT: The embryonal axis bears the plumule (future shoot) and radicle (future root).
Statement (B) is CORRECT: In monocots/grasses, the plumule is enclosed in a protective cylindrical sheath called the coleoptile, and the radicle is enclosed in the coleorhiza.
Statement (C) is CORRECT: Upon germination, the radicle penetrates downward into the soil to establish the primary seminal root system.
Statement (D) is INCORRECT: In monocot seeds (including sorghum, maize, wheat), the single shield-shaped cotyledon is called the Scutellum, which absorbs nutrients from the endosperm. 'Husk' refers to the protective glumes/palea/lemma, not the cotyledon.

Therefore, statements (A), (B), and (C) are correct. Correct Answer: Option 1 ((A), (B) and (C) only).

विस्तृत व्याख्या:

Morphology of Monocot Seeds (एकबीजपत्री बीज की संरचना):

Statement (A) is CORRECT: The embryonal axis bears the plumule (future shoot) and radicle (future root).
Statement (B) is CORRECT: In monocots/grasses, the plumule is enclosed in a protective cylindrical sheath called the coleoptile, and the radicle is enclosed in the coleorhiza.
Statement (C) is CORRECT: Upon germination, the radicle penetrates downward into the soil to establish the primary seminal root system.
Statement (D) is INCORRECT: In monocot seeds (including sorghum, maize, wheat), the single shield-shaped cotyledon is called the Scutellum (स्कुटेलम), which absorbs nutrients from the endosperm. 'Husk' refers to the protective glumes/palea/lemma, not the cotyledon.

Therefore, statements (A), (B), and (C) are correct. Correct Answer: Option 1 ((A), (B) and (C) only).

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

Q.25

ICAR AIEEA PG 2024 - Plant Sciences

MCQ (Single Correct) +4 −1

Which of the following statements are INCORRECT about 'Enforced seed dormancy'?
(A) Enforced seed dormancy occurs due to certain genetical and physiological factors.
(B) Enforced seed dormancy is truly a specific character of the seeds.
(C) High soil temperature and $\text{NO}_3$ content of the surface soil may help break the enforced seed dormancy.
(D) Cultivation practices may also break the enforced seed dormancy by exposing the seeds to better aeration.
Choose the correct answer from the options given below:

'बाध्यकारी बीज प्रसुप्ति' (Enforced seed dormancy) के बारे में

निम्नलिखित में से कौन से कथन गलत (INCORRECT) हैं?
(A) बाध्यकारी बीज प्रसुप्ति कुछ आनुवंशिक और कार्यिकीय कारकों के कारण होती है।
(B) बाध्यकारी बीज प्रसुप्ति वास्तव में बीजों का एक विशिष्ट अंतर्निहित लक्षण है।
(C) उच्च मृदा तापमान और सतही मृदा में $\text{NO}_3$ की मात्रा बाध्यकारी बीज प्रसुप्ति को तोड़ने में मदद कर सकती है।
(D) जुताई क्रियाएं (cultivation practices) भी बीजों को बेहतर वातन के संपर्क में लाकर बाध्यकारी प्रसुप्ति को तोड़ सकती हैं।
नीचे दिए गए विकल्पों में से सही उत्तर चुनिए:

(A) and (B) only केवल (A) और (A) and (C) only केवल (A) और (C) (A) and (D) only केवल (A) और (D) (B) and (D) only केवल (B) और (D)

Types of Seed Dormancy:

Innate (Primary) Dormancy: An intrinsic physiological or anatomical property of the seed determined by its genetics and maternal environment.
Enforced Dormancy:
- Caused solely by an unfavourable external environment (e.g., deep burial, lack of moisture, deficient aeration, excessive soil compaction).
The seed itself is non-dormant and capable of immediate germination as soon as the environmental limitation is removed.
Hence, it does not arise from genetic/physiological blockades in the seed, nor is it a specific inherent character of the seed. Therefore, (A) and (B) are INCORRECT statements.

Statements (C) and (D) are correct: Soil disturbances, tillage (aeration), diurnal temperature fluctuations, and nitrate salts trigger germination by terminating enforced dormancy.
Correct Answer: Option 1 ((A) and (B) only).

विस्तृत व्याख्या:

Types of Seed Dormancy (बीज प्रसुप्ति के प्रकार - Harper, 1957):

Innate (Primary) Dormancy: An intrinsic physiological or anatomical property of the seed determined by its genetics and maternal environment.
Enforced Dormancy (बाध्यकारी प्रसुप्ति):
- Caused solely by an unfavourable external environment (e.g., deep burial, lack of moisture, deficient aeration, excessive soil compaction).
The seed itself is non-dormant and capable of immediate germination as soon as the environmental limitation is removed.
Hence, it does not arise from genetic/physiological blockades in the seed, nor is it a specific inherent character of the seed. Therefore, (A) and (B) are INCORRECT statements.

Statements (C) and (D) are correct: Soil disturbances, tillage (aeration), diurnal temperature fluctuations, and nitrate salts trigger germination by terminating enforced dormancy.
Correct Answer: Option 1 ((A) and (B) only).